Calculating the rate on an amortized loan

Suppose you borrow $$500,000$ to buy a house. If your

monthly payments on the $15-$year mortgage are $$4,500,$

what interest rate are you paying? State your answer as an

APR

$$500,000\mathrm{.}00=$$$4,500\mathrm{.}00**\frac{1-[\frac{1}{(1+r{)}^{180}}]}{r},=>r=$

$0\mathrm{.}0059x12=7\mathrm{.}02\%$APR

Suppose you borrow $$40,000$ to buy a car. If your monthly

payments on the $5-$year loan are $$800,$ what interest rate are

you paying? State your answer as an APR

Suppose you borrow $$1,000,000$ to buy a house. If your

monthly payments on the $30-$year mortgage are $$5,700,$

what interest rate are you paying? State your answer as an

APR

Suppose you borrow $$250,000$ to buy a house. If your

monthly payments on the $15-$year mortgage are $$1,900,$

what interest rate are you paying? State your answer as an

APR