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Metamath Proof Explorer

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 ⊢ φ → A = B
Assertion xnegeqd ⊢ φ → − A = − B

Proof

Step Hyp Ref Expression
1 xnegeqd.1 ⊢ φ → A = B
2 xnegeq ⊢ A = B → − A = − B
3 1 2 syl ⊢ φ → − A = − B