Use the graph of f(x) shown below to answer the questions. If there is more than one answer, enter your answers separated by commas. If there is no answer, enter NONE. f(x) (a) Find the x-value(s) of the critical points of f on the interval (-1, 5). X = (b) Find the x-values of the global minimum and global maximum of fon the interval [-1, 1] . global minimum: x = global maximum: x =