\[\boxed{\text{321\ (321).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[y = (x + 5)^{2} - 9\]
\[\boxed{\text{321.}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[x_{1} + x_{2} = 2a - 3\]
\[x_{1} \cdot x_{2} = a^{2} - 3\]
\[2(2a - 3) = a^{2} - 3\]
\[4a - 6 = a^{2} - 3\]
\[a^{2} - 4a + 3 = 0\]
\[D_{1} = 4 - 3 = 1\]
\[a_{1} = 2 + 1 = 3;\]
\[a_{2} = 2 - 1 = 1.\]
\[Ответ:при\ a = 3;\ \ a = 1.\]