Joe negotiates a $65,000 mortgage on a house with monthly payments of $500 for the first year, $600 for the second year, and $700 until the final payment. The first payment is due one month after the loan. The annual interest rate is 12% convertible monthly. Find the outstanding balance to the nearest $500 on Joe's mortgage immediately after the 36th payment. The answer is 67,495.935, but I'm not sure how to get there