And to simplify this, both of these equations, actually the top one and the bottom one, both sides are divisible by 2n. I mean, 0 is divisible by anything. It'll be just 0. So let's divide the top equation by 2n and see what we get. If we divide the top equation by 2n, we can even see it here. This will become just 1. That goes away, and then those go away, and you would just be left with, you are left with negative times the mean, the negative mean of the x, y's.