Answer :
[tex]\frac{x^2}{6}=w-y\\
x^2=6(w-y)\\
x=\sqrt{6(w-y)} \vee x=-\sqrt{6(w-y)}[/tex]
Well you multiply it by 6 so it moves side.
Then square root is so it is just x by it side.
SO the answer is...
x = *square root* 6(w-y)