A home security system costs $9/month in electricity costs (you may assume this is a fixed cost over the duration of the time involved in this question). A new security system costs $1500 to purchase and lasts for 8 years.
Determine a rational function that gives the annual cost of a security system as a function of the number of years you own the system. Using this function determine the average annual cost of the security system given above.
The Attempt at a Solution
I got C(x)=(1500+108n)/n, where n is the number of years.
What would be the "average annual cost" of the security system given above?