Tìm x biết: x(x-1)+x-1=0

$x(x-1)+x-1=0$

$↔x^2-x+x-1=0$

$↔x^2-1=0$

$↔x^2=1$

\(↔\left[ \begin{array}{l}x=\sqrt{1}\\x=-\sqrt{1}\end{array} \right.\)

\(↔\left[ \begin{array}{l}x=1\\x=-1\end{array} \right.\)