Answer:
x = 33°
Explanation:
Vertically opposite angles:
Vertically opposite angles are congruent.
∠AOB = ∠DOC
4x - 6 = 2x + 60
Add 6 to both sides,
4x = 2x + 60 + 6
4x = 2x + 66
Subtract 2x from both sides,
4x - 2x = 66
2x = 66
Divide both sides by 2
x = 66 ÷ 2

∠AOB = 4x - 6
= 4*33 -6
= 132 - 6
∠AOB = 126°
∠DOC = 126°