Jeanie drank 1/3 cup of juice and harry 1/4 drank cup of juice . how much juice did they drink altogether?

7/12
step 1
make the denominators the same :4/12 and 3/12
step 2 
add:4/12+3/12=7/12

Do the inverse operation

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.