Find the interest rates earned on each of the following. Round your answers to the nearest whole number.

1. You borrow $700 and promise to pay back $798 at the end of 8 year.

-------%

2. You lend $700 and the borrower promises to pay you $798 at the end of 8 year.

-------%

3. You borrow $71,000 and promise to pay back $182,127 at the end of 6 years.

-------%

4. You borrow $15,000 and promise to make payments of $4,058.60 at the end of each year for 5 years.

--------%

Can you explain, the steps...how to solve the formula ?