Translate the word phrase into a variable expression1. 15 less than a number.

Lets just say for funzies that "a number" is represented by a variable, say n. We need something that is 15 less than n. This means that subtraction is necessary. The equation representing 15 less than a number is n-15

I would be n-15 because when is says less then a number it means something or (n) or (x) - what ever number you need in this case (15)

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.