Please help.
I need which letters to click

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.

A: 18/15b : 7 - -8 = 15 , 12 - -6 = 18 the y variable always goes over the x variables, c : same thing a