| Step | Hyp | Ref | Expression | 
						
							| 0 |  | cA | ⊢ 𝐴 | 
						
							| 1 |  | cc | ⊢ ℂ | 
						
							| 2 | 0 1 | wcel | ⊢ 𝐴  ∈  ℂ | 
						
							| 3 |  | cB | ⊢ 𝐵 | 
						
							| 4 | 3 1 | wcel | ⊢ 𝐵  ∈  ℂ | 
						
							| 5 |  | cC | ⊢ 𝐶 | 
						
							| 6 |  | chba | ⊢  ℋ | 
						
							| 7 | 5 6 | wcel | ⊢ 𝐶  ∈   ℋ | 
						
							| 8 | 2 4 7 | w3a | ⊢ ( 𝐴  ∈  ℂ  ∧  𝐵  ∈  ℂ  ∧  𝐶  ∈   ℋ ) | 
						
							| 9 |  | caddc | ⊢  + | 
						
							| 10 | 0 3 9 | co | ⊢ ( 𝐴  +  𝐵 ) | 
						
							| 11 |  | csm | ⊢  ·ℎ | 
						
							| 12 | 10 5 11 | co | ⊢ ( ( 𝐴  +  𝐵 )  ·ℎ  𝐶 ) | 
						
							| 13 | 0 5 11 | co | ⊢ ( 𝐴  ·ℎ  𝐶 ) | 
						
							| 14 |  | cva | ⊢  +ℎ | 
						
							| 15 | 3 5 11 | co | ⊢ ( 𝐵  ·ℎ  𝐶 ) | 
						
							| 16 | 13 15 14 | co | ⊢ ( ( 𝐴  ·ℎ  𝐶 )  +ℎ  ( 𝐵  ·ℎ  𝐶 ) ) | 
						
							| 17 | 12 16 | wceq | ⊢ ( ( 𝐴  +  𝐵 )  ·ℎ  𝐶 )  =  ( ( 𝐴  ·ℎ  𝐶 )  +ℎ  ( 𝐵  ·ℎ  𝐶 ) ) | 
						
							| 18 | 8 17 | wi | ⊢ ( ( 𝐴  ∈  ℂ  ∧  𝐵  ∈  ℂ  ∧  𝐶  ∈   ℋ )  →  ( ( 𝐴  +  𝐵 )  ·ℎ  𝐶 )  =  ( ( 𝐴  ·ℎ  𝐶 )  +ℎ  ( 𝐵  ·ℎ  𝐶 ) ) ) |