This top line over here is y1 squared. Then I'm going to distribute this 2y1. This is going to be minus 2y1mx1, that's just that times that, minus 2y1b and then plus, and now let's expand mx1 plus b squared. That's going to be m squared x1 squared plus 2 times mx1 times b plus b squared. All I did, if this was a plus b squared, this is a squared plus 2ab plus b squared. We're just going to do that for each of these terms, or each of these colors I guess you could say. Now let's move to the second term.