So in this blue interval right over there, and actually let me put 4 5ths in a different color so we see that it's not part of that interval. So in this light blue interval right here between zero and 4 5ths, g prime of x is greater than zero, so we know our function is increasing. And so let's see what's happening to the right of this. And the easiest value to try out would just be 1. So let's try out x equals 1. It's in that interval. So when x equals 1, I'll just write g prime of 1 is equal to 4 minus 5, which is equal to negative 1.