| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cnfldbas |  | 
						
							| 2 | 1 | a1i |  | 
						
							| 3 |  | cnfldadd |  | 
						
							| 4 | 3 | a1i |  | 
						
							| 5 |  | cnfldmul |  | 
						
							| 6 | 5 | a1i |  | 
						
							| 7 |  | addcl |  | 
						
							| 8 |  | addass |  | 
						
							| 9 |  | 0cn |  | 
						
							| 10 |  | addlid |  | 
						
							| 11 |  | negcl |  | 
						
							| 12 |  | addcom |  | 
						
							| 13 | 11 12 | mpancom |  | 
						
							| 14 |  | negid |  | 
						
							| 15 | 13 14 | eqtrd |  | 
						
							| 16 | 1 3 7 8 9 10 11 15 | isgrpi |  | 
						
							| 17 | 16 | a1i |  | 
						
							| 18 |  | mulcl |  | 
						
							| 19 | 18 | 3adant1 |  | 
						
							| 20 |  | mulass |  | 
						
							| 21 | 20 | adantl |  | 
						
							| 22 |  | adddi |  | 
						
							| 23 | 22 | adantl |  | 
						
							| 24 |  | adddir |  | 
						
							| 25 | 24 | adantl |  | 
						
							| 26 |  | 1cnd |  | 
						
							| 27 |  | mullid |  | 
						
							| 28 | 27 | adantl |  | 
						
							| 29 |  | mulrid |  | 
						
							| 30 | 29 | adantl |  | 
						
							| 31 |  | mulcom |  | 
						
							| 32 | 31 | 3adant1 |  | 
						
							| 33 | 2 4 6 17 19 21 23 25 26 28 30 32 | iscrngd |  | 
						
							| 34 | 33 | mptru |  |