Step-by-step explanation:
angle AOB = x+3
angle AOC = 2x + 11
angle BOC = 4x-7
angle AOC = angle AOB + angle BOC
=> 2x +11 = (x+3) + (4x-7)
2x +11 = 5x - 4
=> 3x = 15
x = 5
subst x = 5 in the given formulas
angle AOB = x +3 =8
angle AOC = 2x + 11 = 21
angle BOC = 4x - 7 = 13
