A cellular phone company offers several different service op…

A cellulаr phоne cоmpаny оffers severаl different service options. One option, for people who plan on using the phone only in emergencies, costs the user $4.20/month plus $0.57/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. [a] Use the function to find the cost of using the cellular phone for 11 minutes in 1 month. [b]