Each of the figures below is made up of six squares. Three of the figures can be folded on the lines to form a cube. Which figure can not be folded into a cube?

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.

Ithink the answer is b.