Perform the indicated operation. assume all variables represent non-negative real numbers

Step-by-step explanation:

To add or subtract radicals, you need to simplify the radicals and then add the radicals

First simplify

OR

Second simplify  

To simplify   you need to find two radicals that =   when you multiply them. One radical needs to be a perfect square and the other needs to be a non perfect square.

Now put it all together

c

step-by-step explanation:

the answer is 21%.