Step-by-step explanation:
120° + 20° + x = 180° ( sum of interior angle. of triangle is 180°)
140° + x = 180°
x = 180° - 140°
x = 40°
Now
y + x = 180° ( supplementary angle)
y + 40° = 180°
y = 180° - 40°
y = 140°
