ГДЗ по алгебре 8 класс Макарычев ФГОС Задание 775

\[\boxed{\text{775.}\text{\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]

\[x^{2} + bx + c = 0,\ \ \]

\[x_{1} = b,\ \ x_{2} = c\]

\[\left\{ \begin{matrix} x_{1} + x_{2} = - b \\ x_{1}x_{2} = c\ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ \ \ \ \ \ }\]

\[\ \left\{ \begin{matrix} b + c = - b \\ bc = c\ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ \ \ \ }\left\{ \begin{matrix} c = - 2b \\ bc = c\ \ \ \\ \end{matrix} \right.\ \text{\ \ }\]

\[b \cdot ( - 2b) = - 2b\]

\[- 2b^{2} + 2b = 0\]

\[- 2b(b - 1) = 0\]

\[b_{1} = 0\ \ \ \ \ \ \ b_{2} = 1\]

\[c_{1} = - 2 \cdot 0 = 0\ \ (c \neq 0)\]

\[c_{2} = - 2 \cdot 1 = - 2.\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \]

\[Ответ:b = 1,\ c = - 2\text{.\ }\]