9514 1404 393
Answer:
x = 12
Step-by-step explanation:
The two marked angles are a linear pair, so are supplementary.
(8x -20)° +(8x +8)° = 180°
16x -12 = 180 . . . . . . . . . . . divide by °, collect terms
16x = 192 . . . . . . . . . . . add 12
x = 12 . . . . . . . . . . . divide by 16
