Answer:
x = 43°
Explanation:
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
The angle around C = 360°
Then angle inside Δ at C = 360° - 283° = 77°
y is an exterior angle of the triangle , then
y = x + 77°
120° = x + 77° ( subtract 77° from both sides )
43° = x