| Step | Hyp | Ref | Expression | 
						
							| 1 |  | negcl |  | 
						
							| 2 |  | cxpadd |  | 
						
							| 3 | 1 2 | syl3an3 |  | 
						
							| 4 |  | simp2 |  | 
						
							| 5 |  | simp3 |  | 
						
							| 6 | 4 5 | negsubd |  | 
						
							| 7 | 6 | oveq2d |  | 
						
							| 8 |  | simp1l |  | 
						
							| 9 |  | simp1r |  | 
						
							| 10 |  | cxpneg |  | 
						
							| 11 | 8 9 5 10 | syl3anc |  | 
						
							| 12 | 11 | oveq2d |  | 
						
							| 13 |  | cxpcl |  | 
						
							| 14 | 8 4 13 | syl2anc |  | 
						
							| 15 |  | cxpcl |  | 
						
							| 16 | 8 5 15 | syl2anc |  | 
						
							| 17 |  | cxpne0 |  | 
						
							| 18 | 8 9 5 17 | syl3anc |  | 
						
							| 19 | 14 16 18 | divrecd |  | 
						
							| 20 | 12 19 | eqtr4d |  | 
						
							| 21 | 3 7 20 | 3eqtr3d |  |