Consider the figure,
∠ACB+∠ACE=180o [Adjacent Angle]
⇒x+x+48=180o
∴2x=132
∴x=66o
Given that AB=AC
⇒∠ABC=∠ACB=x=66o
Consider △ABC,
By Angle Sum Property, sum of all interior angles =180o
∠ABC+∠BCA+∠BAC=180o
⇒66+66+∠BAC=180o
∴∠BAC=48o
∴∠y=180−∠BAC=180−48=132o
∴y=132o