Write and solve a system of equations to model the situation​

You have $600,000 saved for retirement. your account earns 5.5% interest. how much, to the nearest dollar, will you be able to pull out each month, if you want to be able to take withdrawals for 20 years?

Ineed with number 6 , explain how to get 1978

For what value of (y) is 3^3/3^y =1/9