Theorem div2negd

Description: Quotient of two negatives. (Contributed by Mario Carneiro, 27-May-2016)

	Ref	Expression
Hypotheses	div1d.1	⊢ ( 𝜑 → 𝐴 ∈ ℂ )
	divcld.2	⊢ ( 𝜑 → 𝐵 ∈ ℂ )
	divcld.3	⊢ ( 𝜑 → 𝐵 ≠ 0 )
Assertion	div2negd	⊢ ( 𝜑 → ( - 𝐴 / - 𝐵 ) = ( 𝐴 / 𝐵 ) )

Proof

Step	Hyp	Ref	Expression
1		div1d.1	⊢ ( 𝜑 → 𝐴 ∈ ℂ )
2		divcld.2	⊢ ( 𝜑 → 𝐵 ∈ ℂ )
3		divcld.3	⊢ ( 𝜑 → 𝐵 ≠ 0 )
4		div2neg	⊢ ( ( 𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ ∧ 𝐵 ≠ 0 ) → ( - 𝐴 / - 𝐵 ) = ( 𝐴 / 𝐵 ) )
5	1 2 3 4	syl3anc	⊢ ( 𝜑 → ( - 𝐴 / - 𝐵 ) = ( 𝐴 / 𝐵 ) )