$6.$ What will be the monthly payment on a home mortgage of $$75,000$ at $12\%$ interest

compounded monthly, to be amortized over $30$ years?

$$771\mathrm{.}46$

$27.$ Three thousand dollars is deposited into an account paying $10\%$ annually to provide three

annual withdrawals of $$1,206\mathrm{.}34$ beginning in one year. How much remains in the account

after the second payment has been withdrawn?

$$1,096\mathrm{.}69$

Can you explain how these questions are answered with formulas? thank you :)