a) \(\Leftrightarrow\left[{}\begin{matrix}3x-7=2x\\3x-7=-2x\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=7\\5x=7\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=7\\x=\frac{7}{5}\end{matrix}\right.\left(TM\right)\)
Câu b lm tương tự