\[x^{2} - 12x - 45 = 0\]
\[D = ( - 12)^{2} - 4 \cdot 1 \cdot ( - 45) =\]
\[= 144 + 180 = 324\]
\[x_{1} = \frac{12 + \sqrt{324}}{2 \cdot 1} = \frac{12 + 18}{2} =\]
\[= \frac{30}{2} = 15\]
\[x_{2} = \frac{12 - \sqrt{324}}{2 \cdot 1} = \frac{12 - 18}{2} =\]
\[= - \frac{6}{2} = - 3\]
\[Ответ:x = 0;\ x = - 9;x = 64;\]
\[x = 15;\ x = - 3.\]