A set of solar panels costs $10800. They will save you $82 dollars per month in electric bills. They need one time maintenance at a cost of $713 after 5 years. They will last 15 years. Assume an annual MARR of 5%. What is the net present value of investing in these cells? That is, what is the present value of all of the benefits minus all of the costs? If it is positive, then they are a good investment. If it is negative, then they are a bad investment.