Need help answer both questions screenshot #1 and screenshot #2. thank your for your time i'll leave positive feedback, thank you again :)

Find the open intervals on which the function is concave upward or concave downward, and find the location of any points of inflection. f(x) = -x#+ 2x + 120x + 36x -5 Select the correct choice below and fill in any answer boxes within your choice. (Type your answer in interval notation.) O A. The function is concave upward on and concave downward on (Use a comma to separate answers as needed.) O B. The function is concave upward on O C. The function is concave downward on Select the correct choice below and fill in any answer boxes within your choice. O A. The point(s) of inflection is/are (Type an ordered pair. Use a comma to separate answers as needed.) O B. There is no point of inflection.Find the point of diminishing returns (x,y) for the function R(x), where R(x) represents revenue (in thousands of dollars) and x represents the amount spent on advertising (in thousands of dollars). R(x) = 10,000 -x + 33x + 600x, OSxs 20 The point of diminishing returns is . (Type an ordered pair.)