\[\left\{ \begin{matrix} a² - 1 > 0 \\ D \leq 0\ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \]
\[= 4 - 8a + 4a^{2} - 8a^{2} + 8 =\]
\[= - 4a^{2} - 8a + 12 \leq 0\]
\[- a^{2} - 2a + 3 = 0\]
\[a_{1} + a_{2} = - 2,\ \ a_{1} \cdot a_{2} = - 3\]
\[a_{1} = - 3,\ \ a_{2} = 1\]
\[(a + 3)(a - 1) \leq 0\]
\[a \leq - 3;\ \ \ \ a \geq 1.\]
\[a² - 1 > 0\]
\[(a + 1)(a - 1) > 0\]
\[a < - 1;\ \ a > 1.\]
\[Ответ:( - \infty;\ - 3\rbrack \cup (1;\ + \infty).\]