x sub i times mu, that's 1 minus x sub i mu. And then you have another one, minus mu x sub i. When you add them together, you get minus 2 x sub i mu. I know it's confusing with me saying sub i and all of that, but it's really no different than when you did a minus b squared, just the variables look a little bit more complicated. And then the last term is minus mu times minus mu, which is plus mu squared. Fair enough. Let me switch colors, just to keep it interesting.