Answer:
x = 12
Step-by-step explanation:
Supplementary angles, sum = 180
10x - 20 + 6x + 8 = 180
16x - 12 = 180
16x = 192
5= 12+3/4x, identify x
-7=3/4x, isolate x
-7(4/3)=x, -28/3=x
:)