A company's average cost per unit when x units are produced is defined to be Total cost Average cost = = Suppose a company's average costs are given by st = 2000 + 85 +0.5x. (a) Express the average-cost formula as a single fraction. Average cost = (b) Write the expression that gives the company's total costs. (Simplify your answer completely.) The consumer expenditure, in dollars, for a commodity is the product of its market price, p, and the number of units demanded, x. Suppose that for a certain commodity, the consumer expenditure is given by 15,000p - 150p2. (a) Factor this in order to find an expression for the number of units demanded. (Simplify your answer completely.) x= units (b) Use (a) to find the number of units demanded when the market price is $36. x = units Suppose that you have $4500 to invest, and you invest x dollars at 11% and the remainder at 2%. Write expressions in x that represent the following values. (a) the amount invested at 2% (b) the interest earned on the x dollars at 11% (c) the interest earned on the money invested at 2% (d) the total interest earned