I don't know if I'm doing justice to it. Let me see if I can imagine a three-dimensional surface that looks something like this. This is the back part that you're not seeing. That's the inside of our three-dimensional surface. We want to find the m and b values that minimize the value on the surface. There's some m and b value right over here that minimizes it. To do that, and I'll actually do the calculation in the next video, we're going to find the partial derivative of this with respect to m, and we're going to find the partial derivative of this with respect to b and set both of them equal to zero.