Answer:
Explanation:
The lines are parallel. The angles marked are exterior angles on the same side of the transversal. That means they are supplementary.
8x + 12x = 180 Combine
20 x = 180 Divide by 20
20x/20 = 180/20
x = 9
8x = 8 * 9 = 72
12x = 12*9 = 108 Add (just to check)
Total 180 Which is exactly what it should be.