Q12 please answer all the questions

Determine the intervals on which the following function is concave up or concave down. Identify any inflection points. f(x ) = 5x4 +40x3- 15 Determine the intervals on which the following functions are concave up or concave down. Select the correct choice below and fill in the answer box(es) to complete your choice. (Simplify your answer. Type your answer in interval notation. Use a comma to separate answers as needed.) O A. The function is concave up on and concave down on O B. The function is concave up on O C. The function is concave down on Locate any inflection points of f. Select the correct choice below and, if necessary, fill in the answer box to complete your choice. O A. An inflection point occurs at x = (Use a comma to separate answers as needed.) O B. There are no inflection points for f