idfk know what I am doing. help :(?

I did the first one but there is no way to check if I'm doing it right

#1 square root of 36x^4 = 6x^2?

#2 square root of c^80d^50 = ?

and when would I need to use a absolute value symbol? (and why if you can explain! please!)

hope someone can help, seems after you graduate (high school) you loose all memory of these things so my friends are no help