Answer:
D. 18
Step-by-step explanation:
The first thing you need to do is subtract 6 from both sides. This makes it cancel out on the left, since 6 - 6 = 0, and subtract 6 from -12:
6 − x = −12
-6 - 6
________
-x = -18
Then divide both sides by -1, because there's a negative sign (-) in front of the x, meaning there's like an invisible 1 there:
-1x = -18
x = 18
