Trish has two containers of water for a camping trip. One container holds 2 times as much as the other. The total amount of water is 21 gallons. How much water is in each container?

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.