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 290 minutes on the phone, and paid $22.25. In another month, you spent 360 minutes on the phone, and paid $24.00. 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.
a. This linear model's slope-intercept equation is.
b. If you spent 140 minutes over the phone in a month, you would pay .
c. If in a month, you paid $26.25 of cell phone bill, you must have spent minutes on the phone in that month.