Any max and min must occur at those points and since there are exactly one of them, it is a good bet that one gives the maximumvalue of fand the other the minimum. I emphasized "value of f" to indicate that, yes, we are talking about the maximum and minimum of f(x). You can probably just see from the values which is the maximum and which the minimum value but since the problem asks you to use the second derivative, if f'(x)= 0 and f"(x)> 0, that x gives a minimum value of f(x). If f'(x)= 0 and f"(x)< 0, that x gives a maximum value of f(x).