Nine years ago a borrower obtained a fixed-rate, fixed-payment mortgage (FRM) loan. Interest was quoted as a 5.10% Annual Percentage Rate (APR), and equal payments of $1,629.59 were to be made at the end of each month for 25 years. What was the amount borrowed? How much remains owed today? Can we compute the unchanging monthly payment if we know what remains owed today but do not know the amount that originally was borrowed?