D. -6x + 12y - 12
First, distribute the -4 and the -2.
-8x + 12y + 4x - 2x - 12
Now, rearrange the expression so the like terms are easier to combine.
-8x + 4x - 2x + 12y - 12
Now, combine the like terms.
-6x + 12y - 12
This is as simple as the expression can get without knowing what the variables are.