William’s typical running speed is 6 mi/h. The difference between his fastest speed and his typical speed is 1.5 mi/h. The equation f minus 1.5 = 6 can be used to represent this problem, where f is William’s fastest speed. What is William’s fastest speed? 4.5 mi/h 5.5 mi/h 6.5 mi/h 7.5 mi/h

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.