Note If you are asked for value s give your answer as a single value e g 17 or a comma separated list e g 1 2 3 or NONE If you are asked for an interval give your answer in interval notation Type INF for oo and INF for o Consider the function f and its derivatives all defined for x 0 f x x5 log x f x x 5x log x f x 9x 20x log z a Find the x values of the critical points of f you are not asked to enter them here and then use the Second Derivative Test when possible to determine the location and types of the extrema Local maxima at x Local minima at x Separate multiple answers by commas and enter NONE if there are no local maxima Separate multiple answers by commas and enter NONE if there are no local minima