And then we are going to square it. So this is the squared error of a line. And I want to find, and what we're going to do over the next few videos, is I want to find the m and b that minimizes this value. That minimizes the squared error of this line right here. So if you view this as the best metric for how good a fit a line is, we're going to try to find the best fitting line for these points. And I'll continue in the next video, because I find that with these very hairy math problems, it's good to kind of just deliver one concept at a time. And it also minimizes my probability of making a mistake.