Gloria is trying to save for retirement. She deposits $400 each month for 20 years into an account that pays 4.2% compounded interest. How much will she have in the account at the end of 20 years round to the nearest dollar)?

The correct answer is addition

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.