f(x) = 2x^3 15x^2- 144x. Answer the following questions. a) f(x) is increasing on: ________________ and f(x) is decreasing on: ______________ b) f(x) is concave upward: _____________ and f(x) is concave downward: ____________ c) f(x) has a local maximum at x = ________ and f(x) has a local minimum at x = ________ d) Does f(x) have an inflection point? If so, give the coordinates of the inflection point.