a gym membership in 2010 was 8700. now it is 6400. what expression equals the percent of change? (the options are 6400/8700, 8700-6400, (8700-6400)/8700, and (8700-6400)/6400

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.