Question

The Gordon family plans to buy a TV. One TV has a purchase price of $330 and an estimated yearly operating cost of $14. The other has a purchase price of $369 and an estimated yearly operating cost of $9. Which TV should the Gordons buy if they plan to keep it for 8 years? Use rational functions to help justify your answer.

Answer 1

for both TV's the total cost can be described as

total cost = (operating cost)(number of years) + purchase price

or, as a function, y = mx + b where x is the number of years, m is the yearly operating cost, and b is the purchase price

write functions for both TVs and calculate which one is cheaper for x = 8 years