Question

Combine like terms w-8w

Answer 1

So you have -8w and w to combine. W is 1*w so start with -8+1 or 1-8 if that is easier for you. Than add the -7 to the w we left behind and you have -7w.

Answer 2

Usually you would have two to add, are you sure this is complete? If this is it then all you do is w-8w, which is -7w.