Add me on hangouts right now bored

The second and fourth answer are correct

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.

4x 20 is 80 but if ther machine is broken then there is none you have to redo the test