Hi, I think this is in the right place. I think it's also very simple but the text book I'm working from just doesn't explain it.

The question is:

If x + p is a factor of ax^{2}+ bx + 3, show that p(b - ap) = 3

According to the book, I think what they want one to do is long division and then, knowing x + p is a factor and therefore remainder = 0, equate the unknown coefficients. But the example in the text is sufficiently different to not explain how to do it with this particular expression. I've got so far with it, and then get totally stuck. I know this is probably very simple but I just can't figure it out.

I can't believe I'm getting stuck so early on. I'm on section 3 of chapter 1. I've had no problems with the first two sections I couldn't work out myself but I'm really stuck on this one! Please help.