Consider the graph of a function f. x Identify the correct statements about the graph. f'(x) < 0 for all x f"(x) < 0 for x < 0 f has one inflection point. f'(x) > 0 for all x f" (x) > 0 for x>0 f has one local minimum and one local maximum. Find the critical valuesc for the function f and apply the Second Derivative Test (if possible) to determine whether each of these values corresponds to a local maximum (Cmax) or minimum (Cmin). f(x) = 3 x - 21x+9 (Use symbolic notation and fractions where needed. Give your answer in the form of a comma separated list, if necessary. Enter DNE if there are no critical values.) Cmax = Cmin =