Please solve on excel and by hand

You purchase a $325,000 town home and you pay 25 percent down. You obtain a 30 -year fixed-rate mortgage with an annual interest rate of 5.75 percent. After ten years (after making 120 payments) you refinance the mortgage for 20 years at a 5.1 percent annual interest rate, since the rates have fallen. a. Show the amortization schedule for the existing mortgage. b. Show the amortization schedule for the refinanced mortgage. c. If at the time of refinancing you are given the option to purchase 1 point for a lower annual rate of 4.90 percent, would you purchase the point? Show the work clearly