If EGH is a straight angle, it equals 180. This means its two parts, EGF and FGH, are supplementary, and add up to 180.
EGF + FGH = 180
2x - 18 + 4x = 180
6x - 18 = 180
6x - 18 + 18 = 180 + 18
6x = 198
6x/6 = 198/6
x = 33
FGH = 4x
FGH = 4(33)
FGH = 132°
BAD is a compound angle. It has 2 parts, BAC and CAD.
BAD = BAC + CAD
BAD = 31 + 24
BAD = 55°