Question

Please h e l p me, I really don't get this.

Answer 1

B is the answer to the question.

Answer 2

Recall that +(-1) = -1. Thus, +(-12) = -12. Then you have -6n - 12 + 4n, or
12-4n (answer)
This is equivalent to 2(2n-6).

You must also check 4(n-3) - 6n. Is the end result the same as 2(2n-6)?