26. [0.76/1.51 Points] DETAILS MY NOTES The DeWitt Company has found that the rate of change of its average cost for a product is C'(x) = 1 100 = 4 +2 where x is the number of units and cost is in dollars. The average cost of producing 4 units is $56.00. (a) Find the average cost function for the product. = 1 100- -x + 30. X 4* (b) Find the average cost of 90 units of the product. (Round your answer to two decimal places.) $ 53.61 Show My Work (Optional) ? Submit Answer 27. [0/1.51 Points] DETAILS MY NOTES Suppose that the marginal revenue for a product is given by -30 MR = + 30 (2x + 1) where x is the number of units and revenue is in dollars. Find the total revenue, R(x). 15 R(x) = 30x + 15 + 2x+1 Show My Work (Optional) ?