And to figure that out, I have to first figure out what are the critical points for my function f, and then which of those critical points do we achieve a minimum or maximum value. And to determine the critical points, we have to find the derivative of our function, because our critical points are just the points at which our derivative is either equal to 0 or undefined. So the derivative of this thing right over here, we're just going to use the power rule several times, and then I guess you could call it the constant rule. But the derivative of x to the third is 3x squared. Derivative of negative 12x is negative 12. And the derivative of a constant, it doesn't change with respect to x, so it's just going to be equal to 0. So we're going to get a critical point when this thing right over here, for some value of x, is either undefined or 0.