Angelika thought of a number N, multiplied it by 7 and added 9. Then she told the result to R to Lisa. In what range can N and R vary?

What are the options

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.