\[x² - 6x - 27 = 0\]
\[D = ( - 6)^{2} - 4 \cdot 1 \cdot ( - 27) =\]
\[= 36 + 108 = 144\]
\[x_{1} = \frac{6 + \sqrt{144}}{2 \cdot 1} = \frac{6 + 12}{2} =\]
\[= \frac{18}{2} = 9;\]
\[x_{2} = \frac{6 - \sqrt{144}}{2 \cdot 1} = \frac{6 - 12}{2} =\]
\[= - \frac{6}{2} = - 3.\]
\[Ответ:x = 9;\ x = - 3.\]