Answer:
y= 14
Explanation:
Given that AC= BC, △ABC is an isosceles triangle.
∠CBA= ∠CAB (base ∠s of isos. △)
∠CBA= 50°
∠ACB +50° +50°= 180° (∠ sum of △ABC)
∠ACB +100°= 180°
∠ACB= 180° -100°
∠ACB= 80°
Given that ∠ACB= (5y +10)°,
(5y +10)°= 80°
5y +10= 80
5y= 80 -10 (-10 on both sides)
5y= 70 (simplify)
y= 70 ÷5 (÷5 throughout)
y= 14