Explain why "dial combinations" are not mathematical combinations expressed by the equation Subscript n Baseline Upper C Subscript x Baseline equals StartFraction n exclamation mark Over x exclamation mark left parenthesis n minus x right parenthesis exclamation mark EndFraction

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.