Question

The phone company splint has a monthly cellular plan where a customer pays a flat monthly fee and then a certain amount of money per minute used on the phone. if a customer uses 470 minutes, the monthly cost will be $162. if the customer uses 540 minutes, the monthly cost will be $183.

a.find an equation in the form y = m x + b , y=mx+b, where x x is the number of monthly minutes used and y y is the total monthly of the splint plan.

Answer 1

162=470m+b and 183=540m+b.
183-162=(540-470)m, 21=70m so m=0.30.
162=470×0.30+b=141+b, b=162-141=21
Therefore y=0.30m+21.