How many books are due back this week?

12,500 x 0.4= 5,000
2/5=0.4%
19,000 x 0.4= 7,600
5,000+7,600= 12,600
1/20=0.05%
12,600 x 0.05= 630
630 books are due this week

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.