3. 5, 9, 10 and 12 are wrong.
You mostly seem to leave out some minus signs:
2(-12 + k) = 2(-12) + 2k = -24 + 2k
-5(3-x) = -15 + 5x
-6(3-d) -18 + 6d
2(l-4) = 2l - 8
-(m-7) = -m + 7
7.7m questions
10.3m answers