This is the solution of your question;
(x-2)^2=6
Let (x-2)^2 have the solution of squaring a binomial in which,this is equal to x^2-4x+4
x^2-4x+4=6
Transpose like terms;x^2-4x=6-4
x^2-4x=2
So the final outcome is;x^2-4x+2
I hope it helps:)
------Domini------