x^2-2x+1=4 ( giup mik voi ) lam theo cach dua ve binh pphuong 1 tong a

`x^2-2x+1=4`

`<=>(x^2-2x+1)-4=0`

`<=>(x-1)^2-2^2=0`

`<=>(x-1-2)(x-1+2)=0`

`<=>(x-3)(x+1)=0`

`<=>` \(\left[ \begin{array}{l}x-3=0\\x+1=0\end{array} \right.\)`<=>` \(\left[ \begin{array}{l}x=3\\x=-1\end{array} \right.\) 

Vậy `x=3;x=-1`