Which of the following is not the same as negative 18?

a: the opposite of the opposite of -18
b: the opposite of 18
c: -18
d: )

Ithink it's the first one ( let me know if it right)

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.