Answer:
y = 21
Step-by-step explanation:
The given angles are vertical angles and has same measurement
4y - 42 = 2y
4y - 2y = 42
2y = 42
The measure of first angle
4y - 42 ➡ 4 × 21 - 42 = 42°
2y ➡ 2 × 21 = 42°
