Consider the following. (If an answer does not exist, enter DNE.) f(x)=x
3
−6x
2
−36x (a) Find the interval(s) on which r is increasing. (Enter your answer using interval notation.) (b) Find the interval(s) on which f is decreasing. (Enter your answer using interval notation.) (c) Find the local minimum and maximum value of f. local minimum value local maximum value