Đáp án:
Giải thích các bước giải:
\(\begin{array}{l}
a.m = - 3\\
Hpt \to \left\{ \begin{array}{l}
3x - 2y = - 3\\
x - 3y = 3
\end{array} \right. \to \left\{ \begin{array}{l}
x = \frac{{ - 15}}{7}\\
y = \frac{{ - 12}}{7}
\end{array} \right.\\
b.\left\{ \begin{array}{l}
x = 3 - my\\
3\left( {\,3 - my} \right) - 2y = m
\end{array} \right. \to \left\{ \begin{array}{l}
x = 3 - my\\
9 - (3m + 2)y = m
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = 3 - my > 0\\
y = \frac{{9 - m}}{{3m + 2}} > 0
\end{array} \right. \to \left[ \begin{array}{l}
\left\{ \begin{array}{l}
9 - m > 0\\
3m + 2 > 0
\end{array} \right.\\
\left\{ \begin{array}{l}
9 - m < 0\\
3m + 2 < 0
\end{array} \right.
\end{array} \right. \to \left[ \begin{array}{l}
9 > m > \frac{{ - 2}}{3}\\
\left\{ \begin{array}{l}
9 < m\\
m < \frac{{ - 2}}{3}
\end{array} \right.(l)
\end{array} \right.\\
\to 9 > m > \frac{{ - 2}}{3}(TMĐB)
\end{array}\)
