A revenue function can be described by the equation () = −22 + 10 − 5 and the cost function can be described by the equation () = 2 − 4, where x represents the number of units sold in thousands. a. How many units have to be sold in order to maximize revenue?

b. What is the profit function?

c. How many units have to be sold in order to maximize the profit? What is the maximum profit?