Đáp án:
\(\left\{ \begin{array}{l}
x = \dfrac{{m + 4}}{3}\\
y = \dfrac{{4 - 2m}}{3}
\end{array} \right.\)
Giải thích các bước giải:
\(\begin{array}{l}
\left\{ \begin{array}{l}
x - y = m\\
2x + y = 4
\end{array} \right.\\
\to \left\{ \begin{array}{l}
3x = m + 4\\
x - y = m
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = \dfrac{{m + 4}}{3}\\
y = x - m = \dfrac{{m + 4}}{3} - m
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = \dfrac{{m + 4}}{3}\\
y = \dfrac{{m + 4 - 3m}}{3}
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = \dfrac{{m + 4}}{3}\\
y = \dfrac{{4 - 2m}}{3}
\end{array} \right.
\end{array}\)
