Решебник по алгебре 8 класс Мерзляк Задание 786

\[\boxed{\mathbf{786\ (786).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[1)\ \frac{2x - 13}{x - 6} = \frac{x + 6}{x}\]

\[\frac{2x - 13}{x - 6} - \frac{x + 6}{x} = 0\]

\[\frac{2x^{2} - 13x - x^{2} + 36}{x(x - 6)} = 0;\ \ \ \ \ \ \]

\[x \neq 0;\ \ \ \ x \neq 6\]

\[x^{2} - 13x + 36 = 0\]

\[x_{1} + x_{2} = 13,\ \ x_{1}x_{2} = 36,\ \]

\[\ x_{1} = 4,\ \ x_{2} = 9\]

\[Ответ:x = 4;x = 9.\]

\[3x^{2} - 4x - 20 =\]

\[= (2x - 5)(x + 2)\]

\[x^{2} - 3x - 10 = 0\]

\[x_{1} + x_{2} = 3,\ \ x_{1}x_{2} = - 10,\ \ \]

\[x_{1} = 5,\ \ \]

\[x_{2} = - 2\ (не\ подходит)\]

\[Ответ:x = 5.\]