please help me. i need to know this answer pretty quick

Work through the following mortgage scenario with Four (4) parts: 1. Borrower has a 30-year mortgage at 6% based on $800,000 What is the monthly principal and interest payment of this mortgage? (4 points) 2. After 8 years, what is the remaining balance? (3 points) 3. At the end of the eighth year ( based on remaining balance found in Number 2 above), the borrower has the ability to refinance that remaining balance with a 20-year mortgage with an interest rate of 4% If the balance in Number 2 above is refinanced with a 20-year mortgage with an interest rate of 4%, what would the new monthly principal and interest payment be for the new loan? (3 points) 4. Assuming that there is a prepayment penalty of $12,000 to pay off the original mortgage used in Number 1 (based on 30 years 6%, $800,000) and $10,000 in costs to obtain the new loan, how many months would you need to hold the property with the new mortgage as described in Number 3 to offset the costs of the refinance? (3 points) Answer all four questions in the space provided