So it's going to be seven to the x squared minus x power. X squared, x squared minus x power. And then we want to multiply that times the derivative of u with respect to x. So u prime of x, well that's going to be two x to the first, which is just two x, minus one. So we're going to multiply this times two x, two x minus one. So there you have it. That is the derivative of y with respect to x.