y = 14 If it’s equilateral then the bottom 2 are the same so it would be 50 + 50 = 100 and because a triangle adds up into 180 then the last angle is 80 degrees and we would then make 5y + 10= 80 we would simplify
5y + 10 - 10 = 80 - 10
5y/5 = 70/5
y = 14