OK, who can explain to me how to solve this: If x^2+2xy+y^2 = 9 then (x+y)^4 = ? I know the answer is "81", I just don't know how to get it. It's starting to frustrate me. I haven't done this stuff in almost ten years, and I can't for the life of me remember how to go about it (although I seem to be getting the hang of some of the other ones...?) Erin TO ------------------------------------------------------------------ To change your Lit-Ideas settings (subscribe/unsub, vacation on/off, digest on/off), visit www.andreas.com/faq-lit-ideas.html