\[\begin{array}{l}
a)\,\, - m\left( {x - m + 3} \right) = m\left( {x - 2} \right) + 6\\
\Leftrightarrow - mx + {m^2} - 3m = mx - 2m + 6\\
\Leftrightarrow 2mx - {m^2} + m + 6 = 0\\
TH1:\,\,m = 0 \Rightarrow 0x + 6 = 0\,\,\left( {vo\,\,nghiem} \right)\\
TH2:\,\,m \ne 0 \Leftrightarrow x = \frac{{{m^2} - m - 6}}{2}\\
b)\,\, - {m^2}\left( {x - 1} \right) + m = x\left( {3m - 2} \right)\\
\Leftrightarrow x\left( {3m - 2} \right) + {m^2}x - {m^2} - m = 0\\
\Leftrightarrow x\left( {{m^2} + 3m - 2} \right) - {m^2} - m = 0\\
TH1:\,\,{m^2} + 3m - 2 = 0 \Leftrightarrow m = \frac{{ - 3 \pm \sqrt {17} }}{2}\\
m = \frac{{ - 3 + \sqrt {17} }}{2} \Rightarrow 0x - 5 + \sqrt {17} = 0\,\,\left( {Vo\,\,nghiem} \right)\\
m = \frac{{ - 3 - \sqrt {17} }}{2} \Rightarrow 0x - 5 - \sqrt {17} = 0\,\,\left( {Vo\,\,nghiem} \right)\\
TH2:\,\,{m^2} + 3m - 2 \ne 0 \Leftrightarrow m \ne \frac{{ - 3 \pm \sqrt {17} }}{2}\\
\Rightarrow Pt\,\,co\,\,nghiem\,\,\,x = \frac{{{m^2} + m}}{{{m^2} + 3m - 2}}
\end{array}\]
