Hoping for some help with concavity, ca

(4 points) Let f(x) = x - 3x- -105x - 5. Find the intervals on which f is increasing or decreasing. Enter your answer as an interval or union of intervals. Use a capital letter 'U' for union. Increasing: (-inf,-5) U (7,inf) Decreasing: (-5,7) List the -values of any local extrema, separated by commas. Enter 'N' if there are none. Local maxima: -5 Local minima: 7 Find the intervals on which f is concave up or concave down. Concave Up: Concave Down: List the -values of any points of inflection, separated by commas. Enter 'N' if there are none. Points of inflection