Question

what values of x will make EF || CD if AB||CD

Answer 1

Hey Mate.

if A || B then,
angle ECD will be
65-25=40
angleFEC+angleDCE=180
so,
40-x=180
x=140

Answer 2

A||B /_ECD

=>65-25=40°

=>/_FEC+/_DCE=180°

40-x=180°

=>x=140°