Answer:
A. 12.7
Explanation:
If line a is parallel to line b, therefore,
(10x - 13.3) = (8x + 12.1) => alternate interior angles theorem
Solve for x
10x - 13.3 = 8x + 12.1
Collect like terms
10x - 8x = 13.3 + 12.1
2x = 25.4
Divide both sides by 2
x = 25.4/2
x = 12.7