Simple...
you have: [tex] \sqrt{120} [/tex]
The best you can do here is simplify the root--->>
You must find a number that is a perfect square--->>
[tex] \sqrt{4} * \sqrt{30} = \sqrt{120} [/tex]
As we know 4 is a perfect root [tex]( \sqrt{4} =2)[/tex] leaving you with....
[tex]2 \sqrt{30} [/tex]
Thus, your answer.