(x-1)(x²-3x+2)=0
⇒\(\left[ \begin{array}{l}x-1=0\\x²-3x+2=0\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x=1\\x²-2x-x+2=0\end{array} \right.\) \(\left[ \begin{array}{l}x=1\\(x-1)(x-2)=0\end{array} \right.\) \(\left[ \begin{array}{l}x=1\\x=2\end{array} \right.\)