We see right here f-prime is positive, positive, positive, and then it goes negative, negative, negative. So we see f-prime is positive over here. And then right when we hit x equals negative two, f-prime becomes negative. f-prime becomes negative. So we know that the function itself, not f-prime, f must be increasing here because f-prime is positive. And then our function f is decreasing here because f-prime is negative. And so this happens at x equals two.