\[a^{2}x - 6 = 3a + 4x\]
\[a^{2}x - 4x = 3a + 6\]
\[x\left( a^{2} - 4 \right) = 3 \bullet (a + 2)\]
\[x(a - 2)(a + 2) = 3 \bullet (a + 2)\]
\[a = 2 \Longrightarrow нет\ решения.\]
\[a = - 2 \Longrightarrow x - любое.\]
\[Ответ:нет\ решения\ при\ a = 2;\ \ \]
\[x - любое\ при\ a = - 2;\]
\[x = \frac{3}{a - 2}\ при\ a \neq \pm 2.\]