So first, let's figure out the derivative of y with respect to x. Well, that's just going to be equal to four. We've seen that many times before. And so what we need to test is, is four, the derivative of y with respect to x, equal to four times, I could write y, but instead of y, let's write four x. I'm gonna put everything in terms of x. So y is equal to four x. So instead of four y, I could write four times four x. All of that over x.