Help number 2 ASAP thank you

What is the similarity ratio of a cube with volume 729m^3 to a cube with volume 3375 m^3

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?

Sole the equation 6n + 9 = -3n - 21 - 6 for n