Answer:
13) Angle DEG + Angle GEF = Angle DEF
5x - 4 + 7x - 8 = 180
12x - 12 = 180
12x = 192
x = 16
Angle GEF = Angle DEH
7(16) - 8 = 9y + 5
104 = 9y + 5
9y = 99
y = 11
14) Angle R + Angle S = 90°
12x - 3 + 7x - 2 = 90
19x - 5 = 90
19x = 95
x = 5
Angle R = 12(5) - 3 = 60 - 3 = 57°
15) Angle P + Angle Q = 180°
4x + 1 + 9x - 3 = 180
13x - 2 = 180
13x = 182
x = 14
Angle Q = 9(14) - 3 = 126 - 3 = 123°