Theorem absnegi

Description: Absolute value of negative. (Contributed by NM, 2-Aug-1999)

	Ref	Expression
Hypothesis	absvalsqi.1	$$⊢A\in ℂ$$
Assertion	absnegi	$$⊢\left|-A\right|=\left|A\right|$$

Proof

Step	Hyp	Ref	Expression
1		absvalsqi.1	$$⊢A\in ℂ$$
2		absneg	$$⊢A\in ℂ\to \left|-A\right|=\left|A\right|$$
3	1 2	ax-mp	$$⊢\left|-A\right|=\left|A\right|$$