\[\boxed{\text{995.\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]
\[D = b^{2} - 4ac\]
\[x^{2} + 2ax + a^{2} - 4 = 0\]
\[a_{1} = 1,\ \ b = 2a,\]
\[\ \ c = a^{2} - 4\]
\[D = (2a)^{2} - 4 \cdot 1 \cdot \left( a^{2} - 4 \right) =\]
\[= 4a^{2} - 4a^{2} + 16 = 16\]
\[x_{1,2} = \frac{- b \pm \sqrt{D}}{2a} = \frac{- 2a \pm 4}{2} =\]
\[= - a \pm 2\]
\[- 6 < - a + 2 < 6\]
\[- 8 < - a < 4\]
\[- 4 < a < 8\]
\[- 6 < - a - 2 < 6\]
\[- 4 < - a < 8\]
\[- 8 < a < 4\]
\[( - 4;4)\]
\[Ответ:при\ \ a \in ( - 4;4)\ \]
\[уравнение\ имеет\ 2\ корня.\]