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| Question 356893:  Hi! I have to write a linear function of the monthly price of a cell phone plan, with x representing the number of minutes used above the maximum allowable minutes included in the plan. I need to lable all variables and state what they represent. Here is the word problem: My family needs 3 cell phones and we anticipate using 800-1500 billable minutes per month. I am given several plans to choose from and I have to decide which one is best. Here is one of the plans: 700 minutes-----.40/each additional minute-----$69.99 for 2 phones/ month---$9.99/ month each additional phone. I just need to see this one example of how to set the linear function up, and I can do all the others. Any help is HUGELY appreciated!!! Thank you!!!
 Answer by ankor@dixie-net.com(22740)
      (Show Source): 
You can put this solution on YOUR website! write a linear function of the monthly price of a cell phone plan, with x representing the number of minutes used above the maximum allowable minutes
 included in the plan.
 I need to lable all variables and state what they represent.
 Here is the word problem: My family needs 3 cell phones and we anticipate
 using 800-1500 billable minutes per month.
 I am given several plans to choose from and I have to decide which one is best.
 Here is one of the plans: 700 minutes-----.40/each additional minute-----$69.99
 for 2 phones/ month---$9.99/ month each additional phone.
 :
 The monthly cost equation for x minutes over 700 is simple, just:
 f(x) = .40x + 69.99 + 9.99
 f(x) = .40x + 79.98
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