Carlos works at an electronics store selling computer equipment. He can earn a bonus if he sells
$10,000 worth of computer equipment this month. So far this month, he has sold $4000 worth of
computer equipment. He hopes to sell additional laptop computers for $800 each to reach his goal.
The function f(x) = 800x + 4000 represents Carlos's total sales as a function of the number of laptop
computers he sells.