This bottom equation right here, let's add the mean of y to both sides of this equation. And I do that so that that cancels out. And then we're left with m, do that in the blue color, show you the same equation. We have m times the mean of the x's, plus b, is equal to the mean of the y's. Now, I actually want to get both of these into mx plus b form. This is actually already there. So you can see that if our line, if our best fitting line is going to be y is equal to mx plus b, we still have to find the m and the b.