Theorem adddid

Description: Distributive law (left-distributivity). (Contributed by Mario Carneiro, 27-May-2016)

	Ref	Expression
Hypotheses	addcld.1	⊢ ( 𝜑 → 𝐴 ∈ ℂ )
	addcld.2	⊢ ( 𝜑 → 𝐵 ∈ ℂ )
	addassd.3	⊢ ( 𝜑 → 𝐶 ∈ ℂ )
Assertion	adddid	⊢ ( 𝜑 → ( 𝐴 · ( 𝐵 + 𝐶 ) ) = ( ( 𝐴 · 𝐵 ) + ( 𝐴 · 𝐶 ) ) )

Proof

Step	Hyp	Ref	Expression
1		addcld.1	⊢ ( 𝜑 → 𝐴 ∈ ℂ )
2		addcld.2	⊢ ( 𝜑 → 𝐵 ∈ ℂ )
3		addassd.3	⊢ ( 𝜑 → 𝐶 ∈ ℂ )
4		adddi	⊢ ( ( 𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ ∧ 𝐶 ∈ ℂ ) → ( 𝐴 · ( 𝐵 + 𝐶 ) ) = ( ( 𝐴 · 𝐵 ) + ( 𝐴 · 𝐶 ) ) )
5	1 2 3 4	syl3anc	⊢ ( 𝜑 → ( 𝐴 · ( 𝐵 + 𝐶 ) ) = ( ( 𝐴 · 𝐵 ) + ( 𝐴 · 𝐶 ) ) )