So the derivative with respect to x of x squared is going to be 2x. And the derivative with respect to x of something to the third power is going to be 3 times that something squared times the derivative of that something with respect to x. So what's the derivative of this with respect to x? Well, the derivative of y with respect to x is just dy dx. And then the derivative of x with respect to x is just 1. So we have minus 1. And on the right-hand side, we just get 0.