Cost, revenue, and profit are in dollars and x is the number of units. Suppose that the marginal revenue for a product is MR = 900 and the marginal cost is MC = 30/x + 4, with a fixed cost of $800 (a) Find the profit or loss from the production and sale of 5 units. There is a ---Select-- of $ (b) How many units will result in a maximum profit? units