Can someone please help me...The interest rate for the first three years of an $80,000 mortgage is 7.2% compounded semiannually. Monthly payments are calculated using a 20-year amortization. a) What will be the principal balance at the end of the three year term? b) What will be the monthly payments if the loan is renewed at 5% compounded semiannually (and the original amortization period is continued)