There are 9 blue, 21 red, 15 yellow, and 5 green marbles in a bag. What is the probability of choosing a blue, then a green? P(blue, green) =

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.