To do that, I'll use the second derivative test to figure out if our function is concave upwards or concave downwards or neither at one of these points. So let's look at the second derivative. So P prime prime of x is going to be equal to negative six x plus negative six x plus 12. And so if we look at, let me make sure I have enough space. So if we look at P prime prime, P prime prime of 3.528. So let's see if I can think this through. So this is between three and four.