| Step | Hyp | Ref | Expression | 
						
							| 1 |  | simpl |  | 
						
							| 2 |  | elfzel1 |  | 
						
							| 3 | 2 | adantl |  | 
						
							| 4 |  | elfzel2 |  | 
						
							| 5 | 4 | adantl |  | 
						
							| 6 | 1 3 5 | 3jca |  | 
						
							| 7 |  | simpl |  | 
						
							| 8 |  | elfzel1 |  | 
						
							| 9 | 8 | adantl |  | 
						
							| 10 |  | elfzel2 |  | 
						
							| 11 | 10 | adantl |  | 
						
							| 12 | 7 9 11 | 3jca |  | 
						
							| 13 |  | zcn |  | 
						
							| 14 |  | zcn |  | 
						
							| 15 |  | pncan |  | 
						
							| 16 |  | pncan2 |  | 
						
							| 17 | 15 16 | oveq12d |  | 
						
							| 18 | 13 14 17 | syl2an |  | 
						
							| 19 | 18 | eleq2d |  | 
						
							| 20 | 19 | 3adant1 |  | 
						
							| 21 |  | 3simpc |  | 
						
							| 22 |  | zaddcl |  | 
						
							| 23 | 22 | 3adant1 |  | 
						
							| 24 |  | simp1 |  | 
						
							| 25 |  | fzrev |  | 
						
							| 26 | 21 23 24 25 | syl12anc |  | 
						
							| 27 | 20 26 | bitr3d |  | 
						
							| 28 | 6 12 27 | pm5.21nd |  |