Well, based on how this has been color-coded ahead of time, you might immediately recognize that this is a composite function, or it could be viewed as a composite function. If you had a v of x, which if you had a function v of x, which is equal to seven to the x power, and you had another function u of x, u of x, which is equal to x squared minus x, then what we have right over here, y, y is equal to seven to something. So it's equal to v of, and it's not just v of x, it's v of u of x. Instead of an x here, you have the whole function u of x, x squared minus x. So it's v of u of x, and the chain rule tells us that the derivative of y with respect to x, and you'll see different notations here, sometimes you'll see it written as the derivative of v with respect to u, so v prime of u of x, times the derivative of u with respect to x, so that's one way you could do it, or you could say that this is equal to, this is equal to the derivative, the derivative of v with respect to x, derivative, or sorry, derivative of v with respect to u, dv du, times the derivative of u with respect to x, derivative of u with respect to x. And so either way, we can apply that right over here. So what's the derivative of v with respect to u?