A phone company has two different long distance phone plans. Plan A charges a monthly fee of $8.51 plus $0.05 per minute. Plan B charges a monthly fee of $6.15 plus $0.08 per minute.
A) Find a function for each long distance plan treating number of minutes used as the independent variable and cost as the dependent variable
x=quantity of minutes, independent variable
y=total cost, variable dependent upon x
B) Graph each of the two functions on the same cartesian plane
Unfortunately, I cannot do that here. However, I can explain how to do it.
Both equations are in slope-intercept format...
m is the slope.
b is the y-intercept, value of y when x=0.
Plan A slope intercept, (0,8.51).
Plan B slope intercept, (0,6.15)
You may also want to establish the x-intercepts, value of x when y=0.
Plot all four points, and draw the appropriate lines.
C) Find the number of minutes for which the cost of plan Z equals the cost of plan B. What is the cost of each plan at this number of minutes? Label this point on the graph
Plan A=Plan B
Let's find the value of y corresponding to this...
Let's check this result with the other equation...
The lines will meet at (78.67,12.44).