SOLUTION: 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

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Question 989232: 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 280 minutes, the monthly cost will be $165. If the customer uses 570 minutes, the monthly cost will be $310.
A) 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 Ringular plan.

Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
.
x=per minute charge; b=flat monthly fee; y=total monthly charge
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mx+b=y
280x+b=$165
570x+b=$310 Subtract second equation from first.
-290x=-$145
x=$0.50
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$0.50(280)+b=$165
$140+b=$165
b=$25
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ANSWER: y=$0.50x+$25
.
CHECK
$0.50(570)+$25=$310
$285+$25=$310
$310=$310