This first term right over here, y1 minus mx1 plus b squared, that's going to be, and we could write this as all going to be the squared error of the line. This first term over here, I'll keep it in blue, is going to be, if we just expand it, y1 squared minus 2 times y1 times mx1 plus b plus mx1 plus b squared. All I did is I just squared this binomial right here. You can imagine this, if this was a minus b, it would be a squared minus 2ab plus b squared. That's all I did. Now I'll just have to do that for each of the terms. Each term is only different by the x and the y coordinates right over here.