Billy is saving up to buy a $400 PS5. He already saved $275. If he has saves $25 a week, how many weeks will it take him to save enough money to buy the PS5? Write an equation for this situation. Use x as your variable. Solve equation

You just purchased two coins at a price of $670 each. because one of the coins is more collectible, you believe that its value will increase at a rate of 7.1 percent per year, while you believe the second coin will only increase at 6.5 percent per year. if you are correct, how much more will the first coin be worth in 15 years?