| Step | Hyp | Ref | Expression | 
						
							| 1 |  | simpll |  | 
						
							| 2 |  | simprl |  | 
						
							| 3 |  | simplr |  | 
						
							| 4 |  | xleadd1a |  | 
						
							| 5 | 4 | ex |  | 
						
							| 6 | 1 2 3 5 | syl3anc |  | 
						
							| 7 |  | simprr |  | 
						
							| 8 |  | xleadd2a |  | 
						
							| 9 | 8 | ex |  | 
						
							| 10 | 3 7 2 9 | syl3anc |  | 
						
							| 11 |  | xaddcl |  | 
						
							| 12 | 11 | adantr |  | 
						
							| 13 |  | xaddcl |  | 
						
							| 14 | 2 3 13 | syl2anc |  | 
						
							| 15 |  | xaddcl |  | 
						
							| 16 | 15 | adantl |  | 
						
							| 17 |  | xrletr |  | 
						
							| 18 | 12 14 16 17 | syl3anc |  | 
						
							| 19 | 6 10 18 | syl2and |  |