Metamath Proof Explorer


Theorem imaeq1d

Description: Equality theorem for image. (Contributed by FL, 15-Dec-2006)

Ref Expression
Hypothesis imaeq1d.1 φA=B
Assertion imaeq1d φAC=BC

Proof

Step Hyp Ref Expression
1 imaeq1d.1 φA=B
2 imaeq1 A=BAC=BC
3 1 2 syl φAC=BC