Consider the following function. (If an answer does not exist, enter DNE.) X f ( x ) =. x2 - 16 (a) Find the interval(s) on which f is increasing. (Enter your answer using interval notation.) Find the interval(s) on which f is decreasing. (Enter your answer using interval notation. ) (b) Find the local minimum value(s). (Enter your answers as a comma-separated list. ) Find the local maximum value(s). (Enter your answers as a comma-separated list.) (c) Find the inflection point. ( x, y ) = Find the interval(s) on which f is concave up. (Enter your answer using interval notation. ) Find the interval(s) on which f is concave down. (Enter your answer using interval notation.)