Five jobs are to be scheduled on three machines (in series). Note jobs must be worked first on machine 1, then on machine 2, and finally on machine 3 (normal order!). Column PT1 is the processing time on the first machine, PT2 is the processing time on the second machine, and PT3 is the processing time on the third machine. What is the sequence that minimizes the makespan for these five jobs

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.