Đáp án:
\(m = - 1,6534566\)
Giải thích các bước giải:
\(\begin{array}{l}
\left\{ \begin{array}{l}
x = m + 1 - my\\
{m^2} + m + {m^2}y + y = 3m - 1
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = m + 1 - my\\
\left( {{m^2} + 1} \right)y = 2m - 1 - {m^2}
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = m + 1 - my\\
y = \dfrac{{2m - 1 - {m^2}}}{{{m^2} + 1}}
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x = \dfrac{{{m^3} + m + {m^2} + 1 - 2{m^2} + m + {m^3}}}{{{m^2} + 1}}\\
y = \dfrac{{2m - 1 - {m^2}}}{{{m^2} + 1}}
\end{array} \right.\\
\to \left\{ \begin{array}{l}
y = \dfrac{{2m - 1 - {m^2}}}{{{m^2} + 1}}\\
x = \dfrac{{2{m^3} - {m^2} + 2m + 1}}{{{m^2} + 1}}
\end{array} \right.\\
Có:x - 2y = 0\\
\to \dfrac{{2{m^3} - {m^2} + 2m + 1}}{{{m^2} + 1}} - \dfrac{{4m - 2 - 2{m^2}}}{{{m^2} + 1}} = 0\\
\to \dfrac{{2{m^3} + {m^2} - 2m + 3}}{{{m^2} + 1}} = 0\\
\to 2{m^3} + {m^2} - 2m + 3 = 0\\
\to m = - 1,6534566
\end{array}\)
