Consider the following function. f(x) = x x-49 (a) Find the critical numbers of f. (Enter your answers as a comma-separated list.) x= (0,0) x (b) Find the open intervals on which the function is increasing or decreasing. (Enter your answers using interval notation. If an answer does not exist, enter DNE.) increasing (-00,-7) U(-7,0) decreasing (0,7) U (7,) (c) Apply the First Derivative Test to identify the relative extremum. (If an answer does not exist, enter DNE.) relative maximum (x, y) = DNE relative minimum (x, y) = DNE )