\[\boxed{\mathbf{708\ (708).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ x² - 12x - 18 = 0\]
\[x_{1} + x_{2} = 12\]
\[x_{1}x_{2} = - 18\]
\[2)\ x² + 2x - 9 = 0\]
\[x_{1} + x_{2} = - 2\]
\[x_{1}x_{2} = - 9\]
\[3)\ 3x² + 7x + 2 = 0\]
\[x_{1} + x_{2} = - \frac{7}{3}\]
\[x_{1}x_{2} = \frac{2}{3}\]
\[4) - 4x^{2} - 8x + 27 = 0\]
\[x_{1} + x_{2} = \frac{8}{- 4} = - 2\]
\[x_{1}x_{2} = - \frac{27}{4} = - 6,75\]