Hello, I stouck in these 5 questions and I hope you can help me to understand them these questions about finance class.

I need the answers as soon as possible

here is the questions

1)Sara purchased a house for $187,500 and took out a mortgage for $150,000 at 6.5% annual interest amortized over 30 years. Five years later she is considering refinancing her mortgage. What is the mortgage balance, or principal balance on Sara's original mortgage?

2) Your cousin Michael is purchasing a home for $225,000 and taking out a $170,000 mortgage at 7% interest amortized over 25 years. He is paying 3 discount points and a 1% origination fee. What annual percentage rate is Michael paying on the loan if it is expected to run the full 25 years?

3) f Michael (in problem 2) knows he is going to stay in this house only five years and then plans to sell the house, what will his APR be?

4) XYZ Federal Salving Bank is considering making a mortgage loan to Jennifer to assist her with her now home purchase. She is asking for a loan of $145,000 to be amortized over 30 years at a 7.5% rate of interest. If the lending officer tells Jennifer she will have to pay 2 points to get the loan, what is the effective rate of interest that XYZ Federal will be earning on the loan, assuming the loan will run for the full 30-year term?

5) Chase is buying a new home with a purchase price of $195,000. He is taking out a 75% loan-to-value mortgage amortized over 25 years with a 6.25% rate of interest. What is Chase's principal balance at the end of three years if he makes all his payments on time?

thank you .