So I can take the derivative of the outside with respect to the inside, that's what we did here, times the derivative of the inside with respect to x. And so if someone were to tell you, if someone were to say, all right, f of x, f of x is equal to the fourth root of x to the third plus four x squared plus seven. And then they said, well, what is f prime of, I don't know, negative three? Well, you would evaluate this at negative three. So let me just do that. So it's 1 4th times, see, you have negative 27. I hope this works out reasonably well, plus 36, plus 36, plus seven to the negative 3 4ths.