Write a recursive formula for each financial situation.
a. You borrow $10,000 at an annual interest rate of 10%, compounded monthly, and each payment is $300.
b. You buy $7000 worth of furniture on a credit card with an annual interest rate of 18.75%, compounded monthly. You plan to pay $250 each month.
c. You invest $8000 at 6%, compounded quarterly, and you deposit $500 every three months. (Quarterly means four times per year.)
d. You enroll in an investment plan that deducts $100 from your monthly paycheck and deposits it into an account with an annual interest rate of 7%, compounded monthly.