They gave you the functions. Did you graph them as suggested?
Here are the lines:
http://www.wolframalpha.com/input/?i=plot+y%3D25%2B10x+,+y+%3D+18%2B15x
Now you can surely answer the questions.
Two cell phone companies have different rate plans. Runfast has monthly charges $25 plus $10 per gig of data. B A &D’s monthly charge is $18 plus 15 per gig of data. Your task is to determine under what circumstances each company has the better pricing. You will derive and solve a set of equations, graph those equations, and evaluate the meanings for these events. Don’t worry; I have a series of questions to guide you through the process. Good luck!
Determine the equation for the monthly charges for Runfast and B A&D.
Runfast= _25+(10*x)____________
BA&D=___18+(15*x)_________
Use your mathematical skill to solve this system of equations using the substitution method. (show your work here)
Graph the results on the accompanying graph as a visual aid. Don’t forget to label which line is for which company.
Why don’t the lines start at the origin?_______________________________________________
What is special about each of the y-intercepts?________________________________________
Which company has the better deal for customers that don’t us much data? How do you know?___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
At what point are the plans the same amount? How do you know?___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Which company has the better deal for customers that use a lot of data? How do you know?___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
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2 answers