So, and that's because F prime is differentiable, so the derivative is definitely, the derivative is zero right at that point of inflection right over here, so if that happens at x equals negative one and over here, then F prime starts increasing, but then it, right at x equals one, then it starts decreasing. So at x equals one, we have another point of inflection, and that's where we have that zero, that the zero, a tangent line with slope zero, and then we're decreasing, decreasing, decreasing, decreasing, decreasing, increasing. All right, so this is going to be another point of inflection, x equals three. So these are our three points of inflection. So this happens, so this happens, happens at x equals negative one, x equals one, and x equals three. So these three points, and on our graph of F prime, where we see F prime goes from decreasing to increasing, or increasing to decreasing, or decreasing to increasing. All right, all right.