Answer:
A. What will your monthly payments be?
B. What will your final payment be?
Explanation:
loan = $521,000
interest rate = 8.6% compounded monthly
loan schedule = 15 years
monthly payment = loan amount / PV annuity factor, 0.7167%, 180 periods* = $521,000 / 100.94786 = $5,161.08
No annuity table will give you the annuity factor for 0.7167%, so you must search for an annuity calculator on the web.
Then I prepared an amortization schedule to determine the balance after the 59th payment (attached file). The balance after the 59th payment is $416,649 + $3,001 in interests = $419,650.