So we get 2x. And so if we distribute this business times the dy dx and times the negative 1, when we multiply it times the dy dx, we get, and actually I'm going to write it over here, so we get plus 3 times y minus x squared times dy dx. And then when we multiply it times the negative 1, we get negative 3 times y minus x squared. And then, of course, all of that is going to be equal to 0. Now all we have to do is take this and put it on the right-hand side. So we'll subtract it from both sides of this equation. So on the left-hand side, and actually all the stuff that's not a dy dx I'm going to write in green.