A cellular phone company offers several different service options. One option, for people who plan on using the phone only in emergencies, costs the user $4.50/month plus $0.59/min for each minute the phone is used. Write a linear function for the monthly cost y of the phone in terms of the number of minutes x the phone is used.?
Use the function to find the cost of using the cellular phone for 18 min in 1 month.
$ ?
