1) Let f(x) = 24x1/3. - x. (a) Find the critical value(s) of f(x). (b) Find the interval(s) on which f(x) is increasing/decreasing (c) Determine whether the critical value(s) are local maxima, local minima, or neither. (d) Find the interval(s) on which f(x) is concave up/concave down.