Respuesta :

DeanR

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