Actually, let me do this in a different color. So this is h prime of 9. So let's think about what that is. Let's take the derivative of both sides of this expression to figure out what the derivative with respect to x of h is. So we get derivative with respect to x of h of x is going to be equal to the derivative with respect to x of all of this business. So I could actually just rewrite it. 3 times f of x plus 2 times g of x.