The phone company NextFell 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 110 minutes, the monthly cost will be $73.5. If the customer uses 760 minutes, the monthly cost will be $301. Find an equation in the form y = m x + b, where x is the number of monthly minutes used and y is the total monthly of the NextFell plan.