Let x = number of months.
a)
People's choice: cost = 10 + 21.93x
Top Co.: cost = 0 + 22.45x, or simply
cost = 22.45x
b) To see for what value of x, the month, the costs are equal, set the cost equations equal and solve for x.
10 + 21.93x = 22.45x
Subtract 10 from both sides.
21.93x = 22.45x - 10
Subtract 22.45x from both sides.
-0.52x = -10
Divide both sides by -0.52.
x = 19.23
Answer: In 19.23 months the costs are the same.
c) Plot the two equations:
y = 21.93x + 10
y = 22.45x
