The phone company NextFell has a monthly cellular plan where

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 150 minutes, the monthly cost will be $106.5. If the customer uses 820 minutes, the monthly cost will be $408.

A) Find an equation in the form y=mx+b,y=mx+b, where xx is the number of monthly minutes used and yy is the total monthly of the NextFell plan.

Answer: y=y=  
   

B) Use your equation to find the total monthly cost if 977 minutes are used.

Answer: If 977 minutes are used, the total cost will be  dollars.

Solution

Points are (150,106.25) ,(820 , 408)

slope=(408-106.25)/(820-150) = .45

Using point slope form

y-408=.45(x-820)

y= .45x +39

B. y=.45(977)+39=$478.65