In each problem, find the following.
(a) A function R(x) that describes the total revenue received
(b) The graph of the function from part (a)
(c) The number of unsold seats that will produce the maximum revenue
(d) The maximum revenue

A charter bus charges a fare of $48 per person, plus $2 per person for each unsold seat on the bus. The bus has 42 seats. Let x represent the number of unsold seats. To find R(x), multiply the number riding, 42 - x, by the price per ticket, 48 + 2x.