Let's figure out the m and b's that give us this. So if I were to take the partial derivative of this expression with respect to m. So the partial derivative of this expression with respect to m. Well, this first term has no m terms in it, so it's a constant from the point of view of m. And just as a reminder, partial derivatives is just like taking a regular derivative, and you're just assuming that everything but the variable that you're taking the partial derivative with respect to, you're assuming everything else is a constant. So in this expression, all the x's, the y's, the b's, the n's, those are all constant. The only variable when we take the partial derivative with respect to m that matters is the m. So this is a constant, there's no m here. This term right over here, we're taking with respect to m. So the derivative of this with respect to m is negative 2, it's kind of the coefficients on the m. So negative 2 times n times the mean of the xy's, that's the partial of this with respect to m. And then this term right here, this term right here has no m's in it, so it's constant with respect to m, so it's partial derivative with respect to m is 0. Then this term here, you have n times the mean of the x squared times m squared. So this is going to be, we're taking the partial derivative with respect to m, so it's going to be 2 times, so it's going to be plus 2 times, 2 times n times the mean of the x squared times m, right?