Let f(x) = 9x3 8. (a) List the critical point(s) of f: 2 (b)f'(x)>0foer Z . (c)f'(x)

Let f(x) = 9x3 8. (a) List the critical point(s) of f: (b) f' (x) > 0 for x e (c) f' (x) < 0 for x e Note: the answers to the above questions can be a value, a list of values, an interval, a union of intervals, or "NONE" if no values exist.