Answer:
14
Step-by-step explanation:
∠AOB is a straight angle, meaning that it is 180°. Since ∠AOC, ∠COD, and ∠DOB are within ∠AOB, the sum of all of the angles is equal to 180°.
∠AOC + ∠COD + ∠DOB = ∠AOB
(5x) + (3x + 30) + (2x + 10) = 180
5x + 3x + 30 + 2x + 10 = 180
10x + 30 + 10 = 180
10x + 40 = 180
10x + 40 - 40 = 180 - 40
10x = 140
10x/10 = 140/10
x = 14
