Please help with all!This is my last question

Problem 3 (10 points) Given the function f (x) = 4x3 - 6x2 - 24x a) Determine the critical numbers for f. b) Using the first derivative, find the intervals of increase and decrease. Write intervals using interval notation. c) Find all relative extrema. d) Using the second derivative, find the intervals of concavity (concave up and concave down). Write intervals in interval notation. e) Find all inflection points. Write answer(s) as ordered-pairs (x,y)