Short Answer: B
Remark
I don't know how much of this is under the root sign. I'm going to restrict my answer to 180. Thanks for posting the Choices. Without them I would not have been able to answer.
Step one
Factor 180 into prime factors.
180 = 2 * 2 * 3 * 3 * 5
Step two
Put this in for 180
square root (180) = sqrt(2*2*3*3*5)
Step three
Obey the root law.
The square root law is for ever pair of = factors you can pull out 1 of them from under the root sign and throw the other one away. So in this case you can pull out a 2 and a 3. That leaves with a 5 under the root sign.
2*3 sqrt(5) x^2
6 * sqrt(5) x^2
I take this to be the answer but since you posted the possibilities, see answer offered under the discussion. You need brackets after the root sign to clarify what the question is. It should be written as √(180x^2) Thank you for posting the comment.
Discussion
If the x^2 is under the root sign as well, then it becomes
6 * sqrt(5) * sqrt(x * x) The same rule applies You have a pair. Take 1 x out and throw the other one away.
6 * sqrt(5) * x or
6x * sqrt(5) <<<<< Answer