>>12
You're almost right. You failed to do something correctly. I'm not quite sure what it is, based on your post, but the way I did it was through the quadratic formula, in which the -b term is also divided by 2*a. You've got -3 where -3/2 or -1.5 should be.
Also,
>>9
It's easier to expand and then subtract because once you've expanded, you've got a free-standing 1 as it's own term, and not as part of another term like (x+1)^3. Subtracting after expansion means that the proper 1's drop out immediately when necessary. All I'm saying is that you should reverse your first two steps, and you're good. Sorry I failed to catch this in my last post.