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 +18x5 - 18x+19 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.) O 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 x coordinates of any inflection points of the graph of f(x). Select the correct choice below and, if necessary, fill in the answer box to complete your choice. O A. x= (Type an exact answer. Use a comma to separate answers as needed.) O B. There are no inflection points.A company manufactures and sells x cellphones per week. The weekly price-demand and cost equations are given below. p = 400 -0.1x and C(x) = 25,000 + 140x (A) What price should the company charge for the phones, and how many phones should be produced to maximize the weekly revenue? What is the maximum weekly revenue? The company should produce phones each week at a price of $ (Round to the nearest cent as needed.) The maximum weekly revenue is $ . (Round to the nearest cent as needed.) (B) What price should the company charge for the phones, and how many phones should be produced to maximize the weekly profit? What is the maximum weekly profit? The company should produce phones each week at a price of $ (Round to the nearest cent as needed.) The maximum weekly profit is $ . (Round to the nearest cent as needed.)