| Step | Hyp | Ref | Expression | 
						
							| 1 |  | simp11 |  | 
						
							| 2 |  | simp12 |  | 
						
							| 3 |  | simp13 |  | 
						
							| 4 |  | simp2l |  | 
						
							| 5 | 4 | znegcld |  | 
						
							| 6 |  | simp2r |  | 
						
							| 7 | 6 | znegcld |  | 
						
							| 8 |  | simp3l |  | 
						
							| 9 |  | simp3r |  | 
						
							| 10 |  | congneg |  | 
						
							| 11 | 1 4 6 9 10 | syl22anc |  | 
						
							| 12 |  | congadd |  | 
						
							| 13 | 1 2 3 5 7 8 11 12 | syl322anc |  | 
						
							| 14 | 2 | zcnd |  | 
						
							| 15 | 4 | zcnd |  | 
						
							| 16 | 14 15 | negsubd |  | 
						
							| 17 | 3 | zcnd |  | 
						
							| 18 | 6 | zcnd |  | 
						
							| 19 | 17 18 | negsubd |  | 
						
							| 20 | 16 19 | oveq12d |  | 
						
							| 21 | 13 20 | breqtrd |  |