So let's think about what g prime is doing on either side of these critical values. And I'll draw a little number line here to help us visualize this. And so, so there we go, a little bit of a number line. And let's see, we care about zero, and we care about four fifths. So let's say this is negative one, this is zero, this is one. And so we have one critical point at, let me do this in magenta. We have one critical point here at x equals zero.