The phone company ringular 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 420 minutes, the monthly cost will be $104. if the customer uses 720 minutes, the monthly cost will be $164.

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