The width of a rectangle measures (4d – 8) centimeters, and its length measures (7d – 3) centimeters. Which expression represents the perimeter, in centimeters, of
the rectangle?

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.