Решебник по алгебре 9 класс Макарычев Задание 414

\[\boxed{\text{414\ (414).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[\textbf{а)}\ \left\{ \begin{matrix} 5x + 2y = 30\ | \cdot ( - 2) \\ 3x + 4y = - 3\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ }\]

\[\ \left\{ \begin{matrix} - 10x - 4y = - 60 \\ 3x + 4y = - 3\ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ ( + )\]

\[\left\{ \begin{matrix} - 7x = - 63\ \ \ \ \\ 3x + 4y = - 3 \\ \end{matrix} \right.\ \text{\ \ \ \ \ }\left\{ \begin{matrix} x = 9\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ 27 + 4y = - 3 \\ \end{matrix} \right.\ \]

\[\left\{ \begin{matrix} x = 9\ \ \ \ \ \ \ \ \\ y = - 7,5. \\ \end{matrix} \right.\ \]

\[Ответ:(9; - 7,5).\]

\[\textbf{б)}\ \left\{ \begin{matrix} 2x - y = 85\ \ \ \ | \cdot ( - 2) \\ 5x - 2y = 200\ \ \ \ \ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \Longrightarrow\]

\[\Longrightarrow \left\{ \begin{matrix} - 4x + 2y = - 170 \\ 5x - 2y = 200\ \ \ \ \ \ \\ \end{matrix} \right.\ ( + )\]

\[\Longrightarrow \left\{ \begin{matrix} x = 30\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ 2y = 4x - 170 \\ \end{matrix} \right.\ \Longrightarrow\]

\[\Longrightarrow \left\{ \begin{matrix} x = 30\ \ \ \ \ \ \ \ \ \ \\ y = 2x - 85 \\ \end{matrix} \right.\ \Longrightarrow \left\{ \begin{matrix} x = 30\ \ \ \ \\ y = - 25. \\ \end{matrix} \right.\ \]

\[Ответ:\ \ (30;\ - 25).\]

\[\boxed{\text{414.}\text{\ }\text{ОК\ ГДЗ\ -\ домашка\ на\ 5}}\]

\[3x - 2y = 1\]

\[2y = 3x - 1\]

\[\textbf{а)}\ y - 2x = 2.\]

\[\textbf{б)}\ 2y = 3x + 4\]

\[2y - 3x = 4.\]

\[\textbf{в)}\ 6x - 4y = 2.\ \]