Answer:
x = 3, ∠ B = 70°, ∠ C = 50°
Explanation:
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
∠ ADC is an exterior angle of the triangle , then
15x + 5 + 22x + 4 = 120 , that is
37x + 9 = 120 ( subtract 9 from both sides )
37x = 111 ( divide both sides by 37 )
x = 3
Thus
∠ B = 22x + 4 = 22(3) + 4 = 66 + 4 = 70°
∠ C = 15x + 5 = 15(3) + 5 = 45 + 5 = 50°