Answer:
C
Explanation:
Add 10x to both sides:
-10x - 135 = 117 + 2x
-10x - 135 + 10x = 117 + 2x + 10x
-135 = 117 + 12x
Subtract 117 from both sides:
-135 - 117 = 117 + 12x - 117
-252 = 12x
Divide both sides by 12:

-21 = x
So the answer is C.
Hope this helps!