Answer the questions for the function f x 3x 3x x 4 L Enter f x f x and f x into your grapher to examine the table b Set the first derivative f x 0 to find any critical values Tip You may wish to graph f x by itself to explore if it has any zeros It can be helpful to know that the formula of f x factors Select the correct choice below and if necessary in the answer boxes within your choice OA There are no critical numbers B The function f has a critical number at x 1 3 at this critical number the second derivative f x 0 Type an exact answer c What conclusion can be made from your answer to part b Select the correct choice below and if necessary fill in the answer box within your choice A the function f is concave down and corresponds to a relative maximum of f x the function f is concave down and corresponds to a relative minimum of f x OA At the critical number x OB At the critical number x OC At the critical number x OD At the critical number x the function f is concave up and corresponds to a relative maximum of f x QE No conclusion can be made using the second derivative test at this critical number the function f is concave up and corresponds to a relative minimum of f x