ГДЗ по алгебре 8 класс Макарычев ФГОС Задание 774

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\[4x^{2} + bx + c = 0,\ \ \]

\[x_{1} = 0,5,\ x_{2} = c\]

\[x^{2} + \frac{b}{4}x + \frac{c}{4} = 0\]

\[\left\{ \begin{matrix} x_{1} + x_{2} = - \frac{b}{4} \\ x_{1}x_{2} = \frac{c}{4}\text{\ \ \ \ \ \ \ \ \ \ } \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ \ \ \ \ \ }\]

\[\left\{ \begin{matrix} 0,5 + c = - \frac{b}{4} \\ 0,5c = \frac{c}{4} \Longrightarrow c = 0 \\ \end{matrix} \right.\ \]

\[- \frac{b}{4} = 0,5 + 0\ \ \ \ \ | \cdot ( - 4)\]

\[b = - 2\]

\[Ответ:b = - 2,\ c = 0\text{.\ }\]