1 câu trả lời
Đáp án:
$\begin{array}{l}
{x_1}.{x_2} - {x_2} - 3{x_1} + 3 = 0\\
\Rightarrow {x_2}\left( {{x_1} - 1} \right) - 3\left( {{x_1} - 1} \right) = 0\\
\Rightarrow \left( {{x_1} - 1} \right)\left( {{x_2} - 3} \right) = 0\\
\Rightarrow \left[ \begin{array}{l}
{x_1} = 1\\
{x_2} = 3
\end{array} \right.
\end{array}$
