Answer:
y = 14
Explanation:
given AC = BC the the triangle is isosceles with base angles congruent , so
∠ B = ∠ A = 50°
the sum of the 3 angles in the triangle = 180° , that is
5y + 10 + 50 + 50 = 180
5y + 110 = 180 ( subtract 110 from both sides )
5y = 70 ( divide both sides by 5 )
y = 14