tìm x biết: 3x(x-2) - x + 2 = 0

* Hướng dẫn giải

$\begin{array}{l}3\mathrm{x}\left(\mathrm{x}-2\right)-\mathrm{x}+2=0\\ 3\mathrm{x}\left(\mathrm{x}-2\right)-\left(\mathrm{x}-2\right)=0\\ \left(\mathrm{x}-2\right)\left(3\mathrm{x}-1\right)=0\\ \Rightarrow \left[\begin{array}{l}\mathrm{x}-2=0\\ 3\mathrm{x}-1=0\end{array}\right.\iff \left[\begin{array}{l}\mathrm{x}=2\\ \mathrm{x}=\frac{1}{3}\end{array}\right.\end{array}$