Consider the equation below. f(x) = x4 − 8x2 + 8 (a) Find the interval on which f is increasing. (Enter your answer in interval notation.)     Find the interval on which f is decreasing. (Enter your answer in interval notation.)     (b) Find the local minimum and maximum values of f. local minimum       local maximum       (c) Find the inflection points. (x, y) =          (smaller x-value) (x, y) =          (larger x-value)Find the interval on which f is concave up. (Enter your answer in interval notation.)     Find the interval on which f is concave down. (Enter your answer in interval notation.)