(x2-2x+1)-4=0
(x-1)2=4
x-1=2 hoặc x-1=-2
x=3 hoặc x=-1
\(\left(x^2-2x+1\right)-4=0\)
\(\Leftrightarrow\left(x-2\right)^2-4=0\)
\(\Leftrightarrow\left(x-2+4\right)\left(x-2-4\right)=0\)
\(\Leftrightarrow\left(x+2\right)\left(x-6\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x+2=0\\x-6=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-2\\x=6\end{cases}}}\)
\(\left(x^2-2x+1\right)-4=0\)
\(x^2-x-x+1=4\)
\(x.\left(x-1\right)-\left(x-1\right)=4\)
\(\left(x-1\right)^2=4\)
=> \(\orbr{\begin{cases}x-1=2\\x-1=-2\end{cases}}\)=> \(\orbr{\begin{cases}x=3\\x=-1\end{cases}}\)