4) Given the function fx) 3x-8-48x2 a) Find the critical values of f(x). b) Find the local max and local min values for fi(x) and indicate if c) Use your answer from (a) to show the intervals when fx) is d) Find f"(x). there is an absolute max and/or absolute min and what they are. increasing and when it is decreasing. Show on which intervals f(x) is concave upward and concave e) downward.