Graph the function using the given viewing window. Find the intervals on which the function is increasing or decreasing and find any relative maxima or minima. Change the viewing window if it seems appropriate for further analysis.
(a) f(x) = - x3 + 6x2 - 9x - 4,
[-3, 7, - 20, 15]
(b) f(x) = 0.2x3 - 0.2x2 - 5x - 4,
[-10, 10m -30, 20]
(c) f(x) = 1.1x4 - 5.3x2 + 4.07,
[-4, 4, -4, 8]