\(2x^2-4x+2=0\\ \Leftrightarrow2\left(x^2-2x+1\right)=0\\ \Leftrightarrow2\left(x-1\right)^2=0\\ \Leftrightarrow\left(x-1\right)^2=0\\ \Leftrightarrow x-1=0\\ \Leftrightarrow x=1\)
\(2x^2-4x+2=0\)
\(\Leftrightarrow x^2-2x+1=0\)
\(\Leftrightarrow\left\{{}x=1}\)