Решебник по алгебре 8 класс Мерзляк Задание 650

\[\boxed{\mathbf{650\ (650).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]

\[1)\ x² + ax + a - 4 = 0\]

\[\left\{ \begin{matrix} x_{1} = 0\ \ \ \ \ \\ a - 4 = 0 \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ \ \ \ }\left\{ \begin{matrix} x_{1} = 0 \\ a = 4\ \\ \end{matrix} \right.\ \]

\[x^{2} + 4x + 4 - 4 = 0\]

\[x(x + 4) = 0\]

\[x_{1} = 0;\ \ x_{2} = - 4\]

\[Ответ:a = 4;\ \ x_{2} = - 4.\]

\[2)\ 4x² + (a - 8)x + a² + a = 0\]

\[Если\ a = 0:\]

\[4x^{2} - 8x = 0\ \]

\[4x(x - 2) = 0\ \ \]

\[x_{2} = 2.\]

\[Если\ \ a = - 1:\]

\[4x^{2} - 9x = 0\ \ \]

\[x(4x - 9) = 0\ \ \]

\[x_{2} = \frac{9}{4} = 2\frac{1}{4}.\]

\[Ответ:a = 0,\ x_{2} = 2;\ \ \ \ \]

\[a = - 1,\ x_{2} = 2\frac{1}{4}.\]

\[3)\ ax² + (a + 3)x + a² - 3a = 0\]

\[3x^{2} + 6x = 0\ \ \]

\[3x(x + 2) = 0\ \]

\[x_{2} = - 2\]

\[Ответ:a = 3;\ \ x_{2} = - 2.\]