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 330 minutes, the monthly cost will be $141.5. If the customer uses 890 minutes, the monthly cost will be $337.5. Required:
a. Find an equation in the form y= mx +b, where x is the number of monthly minutes used and y is the total monthly of the Splint plan.
b. Use your equation to find the total monthly cost if 624 minutes are used

a) $141.5 = 330m + b Equation 1

$337.5 = 890m + b Equation 2

b) $244.4

Step-by-step explanation:

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 330 minutes, the monthly cost will be $141.5. If the customer uses 890 minutes, the monthly cost will be $337.5.

Required:

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

If a customer uses 330 minutes, the monthly cost will be $141.5.

y = mx + b

$141.5 = 330m + b

If the customer uses 890 minutes, the monthly cost will be $337.5.

$337.5 = 890m + b

Combining the equations

$141.5 = 330m + b Equation 1

$337.5 = 890m + b Equation 2

b. Use your equation to find the total monthly cost if 624 minutes are used

Combining the equations

$141.5 = 330m + b Equation 1

$337.5 = 890m + b Equation 2

We Subtract Equation 2 from 1

-196 = -560m

m = -196/-560

m = 0.35

$337.5 = 890m + b Equation 2

$337.5 = 890 × 0.35 + b

$337.5 - 311.5 = b

b = 26

When x = 624

y = 624× m + b

m = 0.35 , b = 26

y = 624 × 0.35 + 26

y = 218.4 + 26

y = $ 244.4

i hope this is what you were looking for.

see attached graph