If y = 3x and x = 2 then y = 6 is this substitution property

Yes, it is the substitution propertyu are subbing in 2 for x...making it y = 3(2)y = 6

Google will togoh

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.