3(5-12)+4 divided by 2 dont know distributive prop on this

Ten times the square of a non-zero number is eqaul to ninety times the number

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 ratio is proportional to 18/21