Theorem xnegeqd

Description: Equality of two extended numbers with -e in front of them. (Contributed by Glauco Siliprandi, 2-Jan-2022)

	Ref	Expression
Hypothesis	xnegeqd.1	$$⊢\phi \to A=B$$
Assertion	xnegeqd	$$⊢\phi \to -A=-B$$

Proof

Step	Hyp	Ref	Expression
1		xnegeqd.1	$$⊢\phi \to A=B$$
2		xnegeq	$$⊢A=B\to -A=-B$$
3	1 2	syl	$$⊢\phi \to -A=-B$$