Find the intervals on which the graph of f is concave upward, the intervals on which the graph of f is concave downward, and the inflection points. f(x) = x - 9x + 19x +4 For what interval(s) of x is the graph of f concave upward? Select the correct choice below and, if necessary, fill in the answer box to complete your choice. O A. (Type your answer in interval notation. Type an exact answer. Use a comma to separate answers as needed.) B. The graph is never concave upward. For what interval(s) of x is the graph of f concave downward? Select the correct choice below and, if necessary, fill in the answer box to complete your choice O A. (Type your answer in interval notation. Type an exact answer. Use a comma to separate answers as needed.) O B. The graph is never concave downward. Determine the Y v coordinates of the inflection point of the graph of f Select the correct choice below and if necessary fill in the answer hay to complete uni