<PRE><B>Question 139514</B>
Sprint has a long distance phone plan that charges a monthly fee of $9.99 plus $0.03 per minute. 
(a) Write down the equation for monthly bill as a function of minutes used.
Bill(x) = 9.99 + 0.03x
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(b) Identify dependent and independent variables.
independent: minutes
dependent: bill
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(c) Graph the function.
{{{graph(400,300,-5,40,-5,15,9.99+0.03x)}}}
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(d) What is the monthly bill if 255 minutes are used for long distance phone calls?
bill(255) = 9.99+0.03*255=17.64
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(e) How many minutes were used for long distance if the long distance phone bill was $ 40.50?
40.50 = 9.99 + 0.03x
0.03x = 40.50- 9.99
x = 1017 minutes
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Cheers,
Stan H.

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