Tamika bell 1/2 of a shed on monday and 2/5 of a shed on tuesday to make a finish building this shed on wednesday. what fraction of the shed did she build on wednesday .a.1/10b.2/5c.3/7d. 9/10

I am assuming bell is built...
1/2= 5/10
2/5=4/10

add them and get 

9/10 ...is already built. so she built the rest on Wednesday which was 1/10

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.