\[x^{2} - 16x + 55 = 0\]
\[D = ( - 16)^{2} - 4 \cdot 1 \cdot 55 =\]
\[= 256 - 220 = 36;\ \ \ \ \sqrt{D} = 6.\]
\[x_{1} = \frac{16 + 6}{2} = \frac{22}{2} = 11;\ \ \ \ \ \]
\[\ x_{2} = \frac{16 - 6}{2} = \frac{10}{2} = 5\]
\[x^{2} - 6x - 55 = 0\]
\[D = ( - 6)^{2} - 4 \cdot 1 \cdot ( - 55) =\]
\[= 36 + 220 = 256;\ \ \ \ \sqrt{D} = 16.\]
\[x_{1} = \frac{6 + 16}{2} = \frac{22}{2} = 11;\ \ \]
\[\text{\ \ \ \ \ \ }x_{2} = \frac{6 - 16}{2} = \frac{- 10}{2} = - 5\]
\[Ответ:для\ любых\ значений\ \text{x.}\]