| Step | Hyp | Ref | Expression | 
						
							| 1 |  | itsclquadb.q |  |-  Q = ( ( A ^ 2 ) + ( B ^ 2 ) ) | 
						
							| 2 |  | itsclquadb.t |  |-  T = -u ( 2 x. ( B x. C ) ) | 
						
							| 3 |  | itsclquadb.u |  |-  U = ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) | 
						
							| 4 |  | simpl1 |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ x e. RR ) -> ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) ) | 
						
							| 5 |  | simp2 |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> R e. RR+ ) | 
						
							| 6 | 5 | adantr |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ x e. RR ) -> R e. RR+ ) | 
						
							| 7 |  | simp3 |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> Y e. RR ) | 
						
							| 8 | 7 | anim1ci |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ x e. RR ) -> ( x e. RR /\ Y e. RR ) ) | 
						
							| 9 | 1 2 3 | itscnhlc0yqe |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ ( x e. RR /\ Y e. RR ) ) -> ( ( ( ( x ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) /\ ( ( A x. x ) + ( B x. Y ) ) = C ) -> ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) ) | 
						
							| 10 | 4 6 8 9 | syl3anc |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ x e. RR ) -> ( ( ( ( x ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) /\ ( ( A x. x ) + ( B x. Y ) ) = C ) -> ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) ) | 
						
							| 11 | 10 | rexlimdva |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( E. x e. RR ( ( ( x ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) /\ ( ( A x. x ) + ( B x. Y ) ) = C ) -> ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) ) | 
						
							| 12 |  | simp3 |  |-  ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) -> C e. RR ) | 
						
							| 13 | 12 | 3ad2ant1 |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> C e. RR ) | 
						
							| 14 |  | simp2 |  |-  ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) -> B e. RR ) | 
						
							| 15 | 14 | 3ad2ant1 |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> B e. RR ) | 
						
							| 16 | 15 7 | remulcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( B x. Y ) e. RR ) | 
						
							| 17 | 13 16 | resubcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( C - ( B x. Y ) ) e. RR ) | 
						
							| 18 |  | simp11l |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> A e. RR ) | 
						
							| 19 |  | simp11r |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> A =/= 0 ) | 
						
							| 20 | 17 18 19 | redivcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C - ( B x. Y ) ) / A ) e. RR ) | 
						
							| 21 | 20 | adantr |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) -> ( ( C - ( B x. Y ) ) / A ) e. RR ) | 
						
							| 22 |  | oveq1 |  |-  ( x = ( ( C - ( B x. Y ) ) / A ) -> ( x ^ 2 ) = ( ( ( C - ( B x. Y ) ) / A ) ^ 2 ) ) | 
						
							| 23 | 22 | oveq1d |  |-  ( x = ( ( C - ( B x. Y ) ) / A ) -> ( ( x ^ 2 ) + ( Y ^ 2 ) ) = ( ( ( ( C - ( B x. Y ) ) / A ) ^ 2 ) + ( Y ^ 2 ) ) ) | 
						
							| 24 | 23 | eqeq1d |  |-  ( x = ( ( C - ( B x. Y ) ) / A ) -> ( ( ( x ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) <-> ( ( ( ( C - ( B x. Y ) ) / A ) ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) ) ) | 
						
							| 25 |  | oveq2 |  |-  ( x = ( ( C - ( B x. Y ) ) / A ) -> ( A x. x ) = ( A x. ( ( C - ( B x. Y ) ) / A ) ) ) | 
						
							| 26 | 25 | oveq1d |  |-  ( x = ( ( C - ( B x. Y ) ) / A ) -> ( ( A x. x ) + ( B x. Y ) ) = ( ( A x. ( ( C - ( B x. Y ) ) / A ) ) + ( B x. Y ) ) ) | 
						
							| 27 | 26 | eqeq1d |  |-  ( x = ( ( C - ( B x. Y ) ) / A ) -> ( ( ( A x. x ) + ( B x. Y ) ) = C <-> ( ( A x. ( ( C - ( B x. Y ) ) / A ) ) + ( B x. Y ) ) = C ) ) | 
						
							| 28 | 24 27 | anbi12d |  |-  ( x = ( ( C - ( B x. Y ) ) / A ) -> ( ( ( ( x ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) /\ ( ( A x. x ) + ( B x. Y ) ) = C ) <-> ( ( ( ( ( C - ( B x. Y ) ) / A ) ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) /\ ( ( A x. ( ( C - ( B x. Y ) ) / A ) ) + ( B x. Y ) ) = C ) ) ) | 
						
							| 29 | 28 | adantl |  |-  ( ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) /\ x = ( ( C - ( B x. Y ) ) / A ) ) -> ( ( ( ( x ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) /\ ( ( A x. x ) + ( B x. Y ) ) = C ) <-> ( ( ( ( ( C - ( B x. Y ) ) / A ) ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) /\ ( ( A x. ( ( C - ( B x. Y ) ) / A ) ) + ( B x. Y ) ) = C ) ) ) | 
						
							| 30 | 17 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( C - ( B x. Y ) ) e. CC ) | 
						
							| 31 | 18 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> A e. CC ) | 
						
							| 32 | 30 31 19 | sqdivd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( C - ( B x. Y ) ) / A ) ^ 2 ) = ( ( ( C - ( B x. Y ) ) ^ 2 ) / ( A ^ 2 ) ) ) | 
						
							| 33 | 13 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> C e. CC ) | 
						
							| 34 | 16 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( B x. Y ) e. CC ) | 
						
							| 35 |  | binom2sub |  |-  ( ( C e. CC /\ ( B x. Y ) e. CC ) -> ( ( C - ( B x. Y ) ) ^ 2 ) = ( ( ( C ^ 2 ) - ( 2 x. ( C x. ( B x. Y ) ) ) ) + ( ( B x. Y ) ^ 2 ) ) ) | 
						
							| 36 | 33 34 35 | syl2anc |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C - ( B x. Y ) ) ^ 2 ) = ( ( ( C ^ 2 ) - ( 2 x. ( C x. ( B x. Y ) ) ) ) + ( ( B x. Y ) ^ 2 ) ) ) | 
						
							| 37 | 13 | resqcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( C ^ 2 ) e. RR ) | 
						
							| 38 | 37 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( C ^ 2 ) e. CC ) | 
						
							| 39 |  | 2re |  |-  2 e. RR | 
						
							| 40 | 39 | a1i |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> 2 e. RR ) | 
						
							| 41 | 13 16 | remulcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( C x. ( B x. Y ) ) e. RR ) | 
						
							| 42 | 40 41 | remulcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( 2 x. ( C x. ( B x. Y ) ) ) e. RR ) | 
						
							| 43 | 42 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( 2 x. ( C x. ( B x. Y ) ) ) e. CC ) | 
						
							| 44 | 38 43 | negsubd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C ^ 2 ) + -u ( 2 x. ( C x. ( B x. Y ) ) ) ) = ( ( C ^ 2 ) - ( 2 x. ( C x. ( B x. Y ) ) ) ) ) | 
						
							| 45 | 15 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> B e. CC ) | 
						
							| 46 | 7 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> Y e. CC ) | 
						
							| 47 | 33 45 46 | mulassd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C x. B ) x. Y ) = ( C x. ( B x. Y ) ) ) | 
						
							| 48 | 47 | eqcomd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( C x. ( B x. Y ) ) = ( ( C x. B ) x. Y ) ) | 
						
							| 49 | 48 | oveq2d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( 2 x. ( C x. ( B x. Y ) ) ) = ( 2 x. ( ( C x. B ) x. Y ) ) ) | 
						
							| 50 |  | 2cnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> 2 e. CC ) | 
						
							| 51 | 13 15 | remulcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( C x. B ) e. RR ) | 
						
							| 52 | 51 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( C x. B ) e. CC ) | 
						
							| 53 | 50 52 46 | mulassd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( 2 x. ( C x. B ) ) x. Y ) = ( 2 x. ( ( C x. B ) x. Y ) ) ) | 
						
							| 54 | 53 | eqcomd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( 2 x. ( ( C x. B ) x. Y ) ) = ( ( 2 x. ( C x. B ) ) x. Y ) ) | 
						
							| 55 | 33 45 | mulcomd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( C x. B ) = ( B x. C ) ) | 
						
							| 56 | 55 | oveq2d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( 2 x. ( C x. B ) ) = ( 2 x. ( B x. C ) ) ) | 
						
							| 57 | 56 | oveq1d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( 2 x. ( C x. B ) ) x. Y ) = ( ( 2 x. ( B x. C ) ) x. Y ) ) | 
						
							| 58 | 49 54 57 | 3eqtrd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( 2 x. ( C x. ( B x. Y ) ) ) = ( ( 2 x. ( B x. C ) ) x. Y ) ) | 
						
							| 59 | 58 | negeqd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> -u ( 2 x. ( C x. ( B x. Y ) ) ) = -u ( ( 2 x. ( B x. C ) ) x. Y ) ) | 
						
							| 60 | 59 | oveq2d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C ^ 2 ) + -u ( 2 x. ( C x. ( B x. Y ) ) ) ) = ( ( C ^ 2 ) + -u ( ( 2 x. ( B x. C ) ) x. Y ) ) ) | 
						
							| 61 | 44 60 | eqtr3d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C ^ 2 ) - ( 2 x. ( C x. ( B x. Y ) ) ) ) = ( ( C ^ 2 ) + -u ( ( 2 x. ( B x. C ) ) x. Y ) ) ) | 
						
							| 62 | 45 46 | sqmuld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( B x. Y ) ^ 2 ) = ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) | 
						
							| 63 | 61 62 | oveq12d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( C ^ 2 ) - ( 2 x. ( C x. ( B x. Y ) ) ) ) + ( ( B x. Y ) ^ 2 ) ) = ( ( ( C ^ 2 ) + -u ( ( 2 x. ( B x. C ) ) x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) ) | 
						
							| 64 | 15 13 | remulcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( B x. C ) e. RR ) | 
						
							| 65 | 40 64 | remulcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( 2 x. ( B x. C ) ) e. RR ) | 
						
							| 66 | 65 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( 2 x. ( B x. C ) ) e. CC ) | 
						
							| 67 | 66 46 | mulneg1d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( -u ( 2 x. ( B x. C ) ) x. Y ) = -u ( ( 2 x. ( B x. C ) ) x. Y ) ) | 
						
							| 68 | 2 | eqcomi |  |-  -u ( 2 x. ( B x. C ) ) = T | 
						
							| 69 | 68 | oveq1i |  |-  ( -u ( 2 x. ( B x. C ) ) x. Y ) = ( T x. Y ) | 
						
							| 70 | 69 | a1i |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( -u ( 2 x. ( B x. C ) ) x. Y ) = ( T x. Y ) ) | 
						
							| 71 | 67 70 | eqtr3d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> -u ( ( 2 x. ( B x. C ) ) x. Y ) = ( T x. Y ) ) | 
						
							| 72 | 71 | oveq2d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C ^ 2 ) + -u ( ( 2 x. ( B x. C ) ) x. Y ) ) = ( ( C ^ 2 ) + ( T x. Y ) ) ) | 
						
							| 73 | 72 | oveq1d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( C ^ 2 ) + -u ( ( 2 x. ( B x. C ) ) x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) = ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) ) | 
						
							| 74 | 36 63 73 | 3eqtrd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C - ( B x. Y ) ) ^ 2 ) = ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) ) | 
						
							| 75 | 74 | oveq1d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( C - ( B x. Y ) ) ^ 2 ) / ( A ^ 2 ) ) = ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) / ( A ^ 2 ) ) ) | 
						
							| 76 | 32 75 | eqtrd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( C - ( B x. Y ) ) / A ) ^ 2 ) = ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) / ( A ^ 2 ) ) ) | 
						
							| 77 |  | resqcl |  |-  ( Y e. RR -> ( Y ^ 2 ) e. RR ) | 
						
							| 78 | 77 | recnd |  |-  ( Y e. RR -> ( Y ^ 2 ) e. CC ) | 
						
							| 79 | 78 | 3ad2ant3 |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( Y ^ 2 ) e. CC ) | 
						
							| 80 | 18 | resqcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( A ^ 2 ) e. RR ) | 
						
							| 81 | 80 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( A ^ 2 ) e. CC ) | 
						
							| 82 |  | recn |  |-  ( A e. RR -> A e. CC ) | 
						
							| 83 |  | sqne0 |  |-  ( A e. CC -> ( ( A ^ 2 ) =/= 0 <-> A =/= 0 ) ) | 
						
							| 84 | 82 83 | syl |  |-  ( A e. RR -> ( ( A ^ 2 ) =/= 0 <-> A =/= 0 ) ) | 
						
							| 85 | 84 | biimpar |  |-  ( ( A e. RR /\ A =/= 0 ) -> ( A ^ 2 ) =/= 0 ) | 
						
							| 86 | 85 | 3ad2ant1 |  |-  ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) -> ( A ^ 2 ) =/= 0 ) | 
						
							| 87 | 86 | 3ad2ant1 |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( A ^ 2 ) =/= 0 ) | 
						
							| 88 | 79 81 87 | divcan2d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( A ^ 2 ) x. ( ( Y ^ 2 ) / ( A ^ 2 ) ) ) = ( Y ^ 2 ) ) | 
						
							| 89 | 88 | eqcomd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( Y ^ 2 ) = ( ( A ^ 2 ) x. ( ( Y ^ 2 ) / ( A ^ 2 ) ) ) ) | 
						
							| 90 | 76 89 | oveq12d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( ( C - ( B x. Y ) ) / A ) ^ 2 ) + ( Y ^ 2 ) ) = ( ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) / ( A ^ 2 ) ) + ( ( A ^ 2 ) x. ( ( Y ^ 2 ) / ( A ^ 2 ) ) ) ) ) | 
						
							| 91 | 81 79 81 87 | divassd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( A ^ 2 ) x. ( Y ^ 2 ) ) / ( A ^ 2 ) ) = ( ( A ^ 2 ) x. ( ( Y ^ 2 ) / ( A ^ 2 ) ) ) ) | 
						
							| 92 | 91 | eqcomd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( A ^ 2 ) x. ( ( Y ^ 2 ) / ( A ^ 2 ) ) ) = ( ( ( A ^ 2 ) x. ( Y ^ 2 ) ) / ( A ^ 2 ) ) ) | 
						
							| 93 | 92 | oveq2d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) / ( A ^ 2 ) ) + ( ( A ^ 2 ) x. ( ( Y ^ 2 ) / ( A ^ 2 ) ) ) ) = ( ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) / ( A ^ 2 ) ) + ( ( ( A ^ 2 ) x. ( Y ^ 2 ) ) / ( A ^ 2 ) ) ) ) | 
						
							| 94 | 65 | renegcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> -u ( 2 x. ( B x. C ) ) e. RR ) | 
						
							| 95 | 2 94 | eqeltrid |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> T e. RR ) | 
						
							| 96 | 95 7 | remulcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( T x. Y ) e. RR ) | 
						
							| 97 | 37 96 | readdcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C ^ 2 ) + ( T x. Y ) ) e. RR ) | 
						
							| 98 | 15 | resqcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( B ^ 2 ) e. RR ) | 
						
							| 99 | 7 | resqcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( Y ^ 2 ) e. RR ) | 
						
							| 100 | 98 99 | remulcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( B ^ 2 ) x. ( Y ^ 2 ) ) e. RR ) | 
						
							| 101 | 97 100 | readdcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) e. RR ) | 
						
							| 102 | 101 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) e. CC ) | 
						
							| 103 | 80 99 | remulcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( A ^ 2 ) x. ( Y ^ 2 ) ) e. RR ) | 
						
							| 104 | 103 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( A ^ 2 ) x. ( Y ^ 2 ) ) e. CC ) | 
						
							| 105 | 102 104 81 87 | divdird |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) + ( ( A ^ 2 ) x. ( Y ^ 2 ) ) ) / ( A ^ 2 ) ) = ( ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) / ( A ^ 2 ) ) + ( ( ( A ^ 2 ) x. ( Y ^ 2 ) ) / ( A ^ 2 ) ) ) ) | 
						
							| 106 | 105 | eqcomd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) / ( A ^ 2 ) ) + ( ( ( A ^ 2 ) x. ( Y ^ 2 ) ) / ( A ^ 2 ) ) ) = ( ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) + ( ( A ^ 2 ) x. ( Y ^ 2 ) ) ) / ( A ^ 2 ) ) ) | 
						
							| 107 | 90 93 106 | 3eqtrd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( ( C - ( B x. Y ) ) / A ) ^ 2 ) + ( Y ^ 2 ) ) = ( ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) + ( ( A ^ 2 ) x. ( Y ^ 2 ) ) ) / ( A ^ 2 ) ) ) | 
						
							| 108 | 107 | adantr |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) -> ( ( ( ( C - ( B x. Y ) ) / A ) ^ 2 ) + ( Y ^ 2 ) ) = ( ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) + ( ( A ^ 2 ) x. ( Y ^ 2 ) ) ) / ( A ^ 2 ) ) ) | 
						
							| 109 | 97 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C ^ 2 ) + ( T x. Y ) ) e. CC ) | 
						
							| 110 | 100 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( B ^ 2 ) x. ( Y ^ 2 ) ) e. CC ) | 
						
							| 111 | 109 110 104 | addassd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) + ( ( A ^ 2 ) x. ( Y ^ 2 ) ) ) = ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( ( B ^ 2 ) x. ( Y ^ 2 ) ) + ( ( A ^ 2 ) x. ( Y ^ 2 ) ) ) ) ) | 
						
							| 112 | 98 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( B ^ 2 ) e. CC ) | 
						
							| 113 | 99 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( Y ^ 2 ) e. CC ) | 
						
							| 114 | 112 81 113 | adddird |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( B ^ 2 ) + ( A ^ 2 ) ) x. ( Y ^ 2 ) ) = ( ( ( B ^ 2 ) x. ( Y ^ 2 ) ) + ( ( A ^ 2 ) x. ( Y ^ 2 ) ) ) ) | 
						
							| 115 | 112 81 | addcomd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( B ^ 2 ) + ( A ^ 2 ) ) = ( ( A ^ 2 ) + ( B ^ 2 ) ) ) | 
						
							| 116 | 115 | oveq1d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( B ^ 2 ) + ( A ^ 2 ) ) x. ( Y ^ 2 ) ) = ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) ) | 
						
							| 117 | 114 116 | eqtr3d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( B ^ 2 ) x. ( Y ^ 2 ) ) + ( ( A ^ 2 ) x. ( Y ^ 2 ) ) ) = ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) ) | 
						
							| 118 | 117 | oveq2d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( ( B ^ 2 ) x. ( Y ^ 2 ) ) + ( ( A ^ 2 ) x. ( Y ^ 2 ) ) ) ) = ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) ) ) | 
						
							| 119 | 96 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( T x. Y ) e. CC ) | 
						
							| 120 | 80 98 | readdcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( A ^ 2 ) + ( B ^ 2 ) ) e. RR ) | 
						
							| 121 | 120 99 | remulcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) e. RR ) | 
						
							| 122 | 121 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) e. CC ) | 
						
							| 123 | 38 119 122 | addassd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) ) = ( ( C ^ 2 ) + ( ( T x. Y ) + ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) ) ) ) | 
						
							| 124 | 119 122 | addcomd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( T x. Y ) + ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) ) = ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) ) | 
						
							| 125 | 124 | oveq2d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C ^ 2 ) + ( ( T x. Y ) + ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) ) ) = ( ( C ^ 2 ) + ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) ) ) | 
						
							| 126 | 123 125 | eqtrd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) ) = ( ( C ^ 2 ) + ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) ) ) | 
						
							| 127 | 111 118 126 | 3eqtrd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) + ( ( A ^ 2 ) x. ( Y ^ 2 ) ) ) = ( ( C ^ 2 ) + ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) ) ) | 
						
							| 128 | 127 | adantr |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) -> ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) + ( ( A ^ 2 ) x. ( Y ^ 2 ) ) ) = ( ( C ^ 2 ) + ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) ) ) | 
						
							| 129 | 128 | oveq1d |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) -> ( ( ( ( ( C ^ 2 ) + ( T x. Y ) ) + ( ( B ^ 2 ) x. ( Y ^ 2 ) ) ) + ( ( A ^ 2 ) x. ( Y ^ 2 ) ) ) / ( A ^ 2 ) ) = ( ( ( C ^ 2 ) + ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) ) / ( A ^ 2 ) ) ) | 
						
							| 130 | 1 | oveq1i |  |-  ( Q x. ( Y ^ 2 ) ) = ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) | 
						
							| 131 | 3 | oveq2i |  |-  ( ( T x. Y ) + U ) = ( ( T x. Y ) + ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) | 
						
							| 132 | 130 131 | oveq12i |  |-  ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( ( T x. Y ) + ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) ) | 
						
							| 133 |  | rpre |  |-  ( R e. RR+ -> R e. RR ) | 
						
							| 134 | 133 | resqcld |  |-  ( R e. RR+ -> ( R ^ 2 ) e. RR ) | 
						
							| 135 | 134 | 3ad2ant2 |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( R ^ 2 ) e. RR ) | 
						
							| 136 | 80 135 | remulcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( A ^ 2 ) x. ( R ^ 2 ) ) e. RR ) | 
						
							| 137 | 37 136 | resubcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) e. RR ) | 
						
							| 138 | 137 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) e. CC ) | 
						
							| 139 | 122 119 138 | addassd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) + ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) = ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( ( T x. Y ) + ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) ) ) | 
						
							| 140 | 132 139 | eqtr4id |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = ( ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) + ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) ) | 
						
							| 141 | 140 | eqeq1d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 <-> ( ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) + ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) = 0 ) ) | 
						
							| 142 | 121 96 | readdcld |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) e. RR ) | 
						
							| 143 | 142 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) e. CC ) | 
						
							| 144 |  | addeq0 |  |-  ( ( ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) e. CC /\ ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) e. CC ) -> ( ( ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) + ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) = 0 <-> ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) = -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) ) | 
						
							| 145 | 143 138 144 | syl2anc |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) + ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) = 0 <-> ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) = -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) ) | 
						
							| 146 | 141 145 | bitrd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 <-> ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) = -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) ) | 
						
							| 147 |  | oveq2 |  |-  ( ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) = -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) -> ( ( C ^ 2 ) + ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) ) = ( ( C ^ 2 ) + -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) ) | 
						
							| 148 | 147 | oveq1d |  |-  ( ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) = -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) -> ( ( ( C ^ 2 ) + ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) ) / ( A ^ 2 ) ) = ( ( ( C ^ 2 ) + -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) / ( A ^ 2 ) ) ) | 
						
							| 149 | 38 138 | negsubd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C ^ 2 ) + -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) = ( ( C ^ 2 ) - ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) ) | 
						
							| 150 | 136 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( A ^ 2 ) x. ( R ^ 2 ) ) e. CC ) | 
						
							| 151 | 38 150 | nncand |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C ^ 2 ) - ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) = ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) | 
						
							| 152 | 149 151 | eqtrd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C ^ 2 ) + -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) = ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) | 
						
							| 153 | 152 | oveq1d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( C ^ 2 ) + -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) / ( A ^ 2 ) ) = ( ( ( A ^ 2 ) x. ( R ^ 2 ) ) / ( A ^ 2 ) ) ) | 
						
							| 154 | 135 | recnd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( R ^ 2 ) e. CC ) | 
						
							| 155 | 154 81 87 | divcan3d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( A ^ 2 ) x. ( R ^ 2 ) ) / ( A ^ 2 ) ) = ( R ^ 2 ) ) | 
						
							| 156 | 153 155 | eqtrd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( C ^ 2 ) + -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) / ( A ^ 2 ) ) = ( R ^ 2 ) ) | 
						
							| 157 | 148 156 | sylan9eqr |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) = -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) ) -> ( ( ( C ^ 2 ) + ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) ) / ( A ^ 2 ) ) = ( R ^ 2 ) ) | 
						
							| 158 | 157 | ex |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) = -u ( ( C ^ 2 ) - ( ( A ^ 2 ) x. ( R ^ 2 ) ) ) -> ( ( ( C ^ 2 ) + ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) ) / ( A ^ 2 ) ) = ( R ^ 2 ) ) ) | 
						
							| 159 | 146 158 | sylbid |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 -> ( ( ( C ^ 2 ) + ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) ) / ( A ^ 2 ) ) = ( R ^ 2 ) ) ) | 
						
							| 160 | 159 | imp |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) -> ( ( ( C ^ 2 ) + ( ( ( ( A ^ 2 ) + ( B ^ 2 ) ) x. ( Y ^ 2 ) ) + ( T x. Y ) ) ) / ( A ^ 2 ) ) = ( R ^ 2 ) ) | 
						
							| 161 | 108 129 160 | 3eqtrd |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) -> ( ( ( ( C - ( B x. Y ) ) / A ) ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) ) | 
						
							| 162 | 30 31 19 | divcan2d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( A x. ( ( C - ( B x. Y ) ) / A ) ) = ( C - ( B x. Y ) ) ) | 
						
							| 163 | 162 | oveq1d |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( A x. ( ( C - ( B x. Y ) ) / A ) ) + ( B x. Y ) ) = ( ( C - ( B x. Y ) ) + ( B x. Y ) ) ) | 
						
							| 164 | 33 34 | npcand |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( C - ( B x. Y ) ) + ( B x. Y ) ) = C ) | 
						
							| 165 | 163 164 | eqtrd |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( A x. ( ( C - ( B x. Y ) ) / A ) ) + ( B x. Y ) ) = C ) | 
						
							| 166 | 165 | adantr |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) -> ( ( A x. ( ( C - ( B x. Y ) ) / A ) ) + ( B x. Y ) ) = C ) | 
						
							| 167 | 161 166 | jca |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) -> ( ( ( ( ( C - ( B x. Y ) ) / A ) ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) /\ ( ( A x. ( ( C - ( B x. Y ) ) / A ) ) + ( B x. Y ) ) = C ) ) | 
						
							| 168 | 21 29 167 | rspcedvd |  |-  ( ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) /\ ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) -> E. x e. RR ( ( ( x ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) /\ ( ( A x. x ) + ( B x. Y ) ) = C ) ) | 
						
							| 169 | 168 | ex |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 -> E. x e. RR ( ( ( x ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) /\ ( ( A x. x ) + ( B x. Y ) ) = C ) ) ) | 
						
							| 170 | 11 169 | impbid |  |-  ( ( ( ( A e. RR /\ A =/= 0 ) /\ B e. RR /\ C e. RR ) /\ R e. RR+ /\ Y e. RR ) -> ( E. x e. RR ( ( ( x ^ 2 ) + ( Y ^ 2 ) ) = ( R ^ 2 ) /\ ( ( A x. x ) + ( B x. Y ) ) = C ) <-> ( ( Q x. ( Y ^ 2 ) ) + ( ( T x. Y ) + U ) ) = 0 ) ) |