Please give the functions and not just the answers. Thank you

Five years ago you obtained a 25-year $200,000 mortgage loan that has an interest rate of 14.5%. You can refinance the loan with a 15- year loan that has an interest rate of 12.0%. If you refinance the first loan, you will have to pay $4,000 of loan origination fees and a 2.5% prepayment penalty on the outstanding principal balance of the original loan. Assume further that you will borrow enough to pay off the remaining principal and all costs associated with refinancing. Original Loan Info Original Loan Amount $200,000.00 Original Interest Rate 14.5% Original Term (years) 25 Periods 12 PMT (monthly) NPERS already paid off Balance outstanding after 5 years Refinancing Loan Info Prepayment Penalty (% 2.5% RATE 12.0% New Term (years) 15 Periods 12 Principal Borrowed $4,000 Loan Origination Fee Prepayment Penalty (Value) Total Cost of loan Total of Loan PMT (monthly) B. How much will you manage to save each month by refinancing? Savings each month from refinancing Hint: If all your calculations are correct this will equal $48.70