Hệ phương trình \(\left\{ \begin{array}{l}3x - 2y = 10\\2x + 3y = - 2\end{array} \right.\). Chọn câu đúng?

* Hướng dẫn giải

\(\begin{array}{l}\,\,\left\{ \begin{array}{l}3x - 2y = 10\\2x + 3y = - 2\end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l}6x - 4y = 20\\6x + 9y = - 6\end{array} \right. \\\Leftrightarrow \left\{ \begin{array}{l}13y = - 26\\3x - 2y = 10\end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l}y = - 2\\3x - 2\left( { - 2} \right) = 10\end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l}y = - 2\\3x = 6\end{array} \right. \\\Leftrightarrow \left\{ \begin{array}{l}x = 2\\y = - 2\end{array} \right.\end{array}\)

⇒ a = -b