Theorem mulm1d

Description: Product with minus one is negative. (Contributed by Mario Carneiro, 27-May-2016)

	Ref	Expression
Hypothesis	mulm1d.1	|- ( ph -> A e. CC )
Assertion	mulm1d	|- ( ph -> ( -u 1 x. A ) = -u A )

Proof

Step	Hyp	Ref	Expression
1		mulm1d.1	|- ( ph -> A e. CC )
2		mulm1	|- ( A e. CC -> ( -u 1 x. A ) = -u A )
3	1 2	syl	|- ( ph -> ( -u 1 x. A ) = -u A )