Let be represents the number of kilowatt-hours used by the customers and the function that gives monthly charge in dollars respectively.

The data infers that Palmetto Electric charges $7.10 plus 6.747 cents per kilowatt-hour (kWh ) for customers using up to 1200 kWh and charges $88.06 plus 5.788 cents per kWh above 1200 kWh.