The profit function of a manufacturer when x units of a commodity are produced and sold...

The profit function of a manufacturer when x units of a commodity are produced and sold is given by

a. Sketch a graph of the profit function.

b. What is the maximum profit, and how many units should be produced to yield it?

c. Compute the difference quotient

and determine the value the difference quotient approaches as h approaches 0. (This quantity is called the marginal profit when x units are sold. It approximates the change in the profit when one additional unit is produced.)