It's one of those problems where they give you a right triangle, and then there is an altitude, and it's usually a variable. They also give you the length of the hypotenuse. I'm not very good at describing what I mean, (sorry) but I believe it should be set up as x+9/18=8/x+9
Do you understand what I'm talking about? I'm so sorry for the terrible description. ^^; The link is to the question, it's the third question on the page.
I've been working on it forever. I believe there is some foil-ing and then un-foil-ing, but I'm really not sure. I just know that I've tried it three different ways, and all of them were wrong. Can someone at least tell me how to set it up? What is it I'm doing wrong?