The following function is provided. (x) = x - 4x - 4 (a) Find the local extrema of f. (Give your answer in the form of a comma-separated list of numbers if needed. Give exact answers. Use symbolic notation and fractions where needed. Enter DNE if there are no local minimum or maximum values.) local minimum value(s): local maximum value(s): (b) Determine the intervals on which / is concave up and on which it is concave down. (Give your answer as an interval in the form (*,*). Use the symbol co for infinity, U for combining intervals, and an appropriate type of parenthesis "(",")", "[","I" depending on whether the interval is open or closed. Enter 3 if the interval is empty. Express numbers in exact form. Use symbolic notation and fractions where needed.) f is concave up on: f is concave down on: (c) Find any points of inflection. (Give your answer as a comma-separated list of points in the form (*,*). Express numbers in exact form. Use symbolic notation and fractions where needed. Enter DNE if there are no such points.) point(s) of inflection