By your cell phone contract, you pay a monthly fee plus some money for each minute you use the phone during the month. In one month, you spent 280 280 minutes on the phone, and paid $30.20 $ 30.20 . In another month, you spent 310 310 minutes on the phone, and paid $32.15 $ 32.15 . Let x be the number of minutes you talk over the phone in a month, and let y be your cell phone bill for that month. Use a linear equation to model your monthly bill based on the number of minutes you talk over the phone.