| Step | Hyp | Ref | Expression | 
						
							| 1 |  | simpl |  | 
						
							| 2 |  | simpr |  | 
						
							| 3 |  | 0cnd |  | 
						
							| 4 | 1 2 3 | 3jca |  | 
						
							| 5 |  | mulsubdivbinom2 |  | 
						
							| 6 | 4 5 | stoic3 |  | 
						
							| 7 |  | simp3l |  | 
						
							| 8 |  | simp1 |  | 
						
							| 9 | 7 8 | mulcld |  | 
						
							| 10 |  | simp2 |  | 
						
							| 11 | 9 10 | addcld |  | 
						
							| 12 | 11 | sqcld |  | 
						
							| 13 | 12 | subid1d |  | 
						
							| 14 | 13 | eqcomd |  | 
						
							| 15 | 14 | oveq1d |  | 
						
							| 16 |  | sqcl |  | 
						
							| 17 | 16 | subid1d |  | 
						
							| 18 | 17 | 3ad2ant2 |  | 
						
							| 19 | 18 | eqcomd |  | 
						
							| 20 | 19 | oveq1d |  | 
						
							| 21 | 20 | oveq2d |  | 
						
							| 22 | 6 15 21 | 3eqtr4d |  |