| Step | Hyp | Ref | Expression | 
						
							| 1 |  | zlmodzxz.z |  | 
						
							| 2 |  | zlmodzxzsub.m |  | 
						
							| 3 | 1 | zlmodzxzlmod |  | 
						
							| 4 | 3 | simpli |  | 
						
							| 5 | 4 | a1i |  | 
						
							| 6 | 1 | zlmodzxzel |  | 
						
							| 7 | 6 | ad2ant2r |  | 
						
							| 8 | 1 | zlmodzxzel |  | 
						
							| 9 | 8 | ad2ant2l |  | 
						
							| 10 |  | eqid |  | 
						
							| 11 |  | eqid |  | 
						
							| 12 | 3 | simpri |  | 
						
							| 13 |  | eqid |  | 
						
							| 14 |  | eqid |  | 
						
							| 15 |  | zring1 |  | 
						
							| 16 | 10 11 2 12 13 14 15 | lmodvsubval2 |  | 
						
							| 17 | 5 7 9 16 | syl3anc |  | 
						
							| 18 |  | 1z |  | 
						
							| 19 |  | zringinvg |  | 
						
							| 20 | 18 19 | mp1i |  | 
						
							| 21 | 20 | eqcomd |  | 
						
							| 22 | 21 | oveq1d |  | 
						
							| 23 | 22 | oveq2d |  | 
						
							| 24 | 17 23 | eqtrd |  |