Answer:
y= 50°
Explanation:
∠A =∠B = y. So, ΔABC is an isosceles triangle.
Sum of angles of triangle = 180
∠A + ∠B + ∠C = 180
y + y + 80 = 180 {add like terms}
2y + 80 = 180 {Subtract 80 from both sides}
2y + 80 - 80 = 180 - 80
2y = 100 {divide both sides by 2}
2y/2 = 100/2
y= 50°