\[a + 2x \geq 3 - ax\]
\[2x + ax \geq 3 - a\]
\[x \cdot (2 + a) \geq 3 - a\]
\[a = - 2 \Longrightarrow нет\ решений\]
\[a < - 2 \Longrightarrow x \leq \frac{3 - a}{2 + a}\]
\[a > - 2 \Longrightarrow x \geq \frac{3 - a}{2 + a}\]