Determine what the value is to complete the square

I'm not entirely sure what you're looking for, but here are your options. If you need a perfect square, I'd go for the 12 and 12, but I hope this helps?

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.