So the key, I guess, property to realize or the key truth to realize is that if f and h are inverses, then h prime of x, h prime of x, is going to be equal to, it's going to be equal to one over f prime of h of x. One over f prime of h of x. And you could now use this in order to figure out what h prime of negative 14 is. Now I know what some of you are thinking because it's exactly what I would be thinking if someone just sprung this on me, is where does this come from? And I would tell you this comes straight out of the chain rule. We know that if a function and its inverse, we know that if we have a function and its inverse, that f of the inverse of our function, so f of h of x, f of h of x, we know that this is going to be equal to x. This literally, this comes out of them being each other's inverses.