Il PC Enterprise charges to rent compact cars for a
fixed amount per day plus a fixed amount for
each mile driven. Batman rented a car for 6 days,
drove it 550 miles and spent $337. Superman
rented the same car for 3 days, drove for 350
miles and spent $185. Set up the system. Let "d"
represent the fixed charge per day and "m"
represent the cost per mile.