Metamath Proof Explorer


Theorem eqeq2

Description: Equality implies equivalence of equalities. (Contributed by NM, 26-May-1993) (Proof shortened by Wolf Lammen, 19-Nov-2019)

Ref Expression
Assertion eqeq2 A=BC=AC=B

Proof

Step Hyp Ref Expression
1 id A=BA=B
2 1 eqeq2d A=BC=AC=B