F of four is equal to three. So zero is between f of two and f of four. And you can see it visually here. There's no way to draw between this point and that point without picking up your pen, without crossing the x-axis, without having a point where your function is equal to zero. And so we can say, so according to the intermediate value theorem, there is a value c such that f of c is equal to zero and two is less than or equal to c is less than or equal to four. So all we're saying is, hey, there must be a value c, and the way I drew it here, that c value is right over here where c is between two and four, where f of c is equal to zero. And this seems all mathy and a little bit confusing sometimes, but it's saying something very intuitive.