\[= a^{2} + 14a + 49 =\]
\[= (a + 7)^{2} > 0;\ \ \ \ \ \ a \neq - 7\]
\[x_{1} = \frac{3a + 5 + a + 7}{4} =\]
\[= \frac{4a + 12}{4} = a + 3\]
\[x_{2} = \frac{3a + 5 - a - 7}{4} =\]
\[= \frac{2a - 2}{4} = 0,5a - 0,5\]
\[Ответ:(2;\ 7).\]