A housepainter mixed 5 gallons of blue paint with every 9 gallons of yellow paint in order to make green paint. Which ratio of gallons of blue paint to gallons of yellow paint will make the same shade of green paint?

Then why is the question on here if you know the answer

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.