Please help

Linda loans her friend $250 with a 5% monthly intrest rate. how much was the whole loan?

At the beginning of year 1, carlos invests $600 at an annual compound interest rate of 4%. he makes no deposits to or withdrawals from the account. which explicit formula can be used to find the account's balance at the beginning of year 5? what is, the balance?

What is the gcf of 20c^3-5c^4+30c^6