These cancel out. It's going to be equal to P plus P times one minus P plus P times one minus P squared. And it's going to keep going on and on and on. Well on the left hand side, all I have is a P times the expected value of X. If I want to solve for the expected value of X, I just divide both sides by P. So I get, and this is kind of neat, through this mathematical gymnastics I now have, I'm just dividing everything by P, both sides. On the left hand side, I just have the expected value of X. If I divide all of these terms by P, this first term becomes one, the second term becomes one minus P. This third term, if I divide by P, becomes plus one minus P squared, so forth and so on.