Answer is y = 5
Why?
This is an equilateral triangle, so both sides of the base will be congruent.
75 = 3x making x = 25
That leaves us with 30 more degrees to make this triangle a triangle.
4*5 = 20
20 + 10 = 30
75 + 75 + 30 = 180
Therefore, 5 is the value of y. Hope this helps!