It's an isosceles triangle, therefore m∠B = m∠C.
We have the equation:
2x + 10 = 3x - 5 subtract 10 from both sides
2x = 3x - 15 subtract 3x from both sides
-x = -15 change the signs
x = 15
m∠B = (2x + 10)°
m∠B = (2 · 15 + 10)° = (30 + 10)° = 40°
We know, the sum of measures of a tringle is equal 180°.
m∠A + m∠B + m∠C = 180°
m∠B = m∠C = 40°
Answer: ∠B = 40° and ∠C = 40°
