Question

задание на картинке,буду очень благодарна)

Answer 1

$\begin{cases}x - 2y = 8 \\ 2x + y = 1 \end{cases} \\ \begin{cases}x = 8 + 2y \\ 2x + y = 1 \end{cases} \\ \overline{ \qquad \qquad \qquad} \\ 2 \times (8 + 2y) + y = 1 \\ 16 + 4y + y = 1 \\ 16 + 5y = 1 \\ 5y = - 15 \\ y = - 3 \\ \overline{ \qquad \qquad \qquad} \\ x = 8 + 2 \times ( - 3) \\ x = 8 - 6 \\ x = 2$

$\begin{cases}4x + 9y = 1 \mid\! \!\times 2 \\ 5x - 18y = - 28 \end{cases} \\ \begin{cases}8x + 18y = 2 \\ 5x - 18y = - 28 \end{cases} \\ \overline{ \qquad \qquad \qquad} \\ 13x = - 26 \\ x = - 2 \\ \overline{ \qquad \qquad \qquad} \\ 4 \times ( - 2) + 9y = 1 \\ - 8 + 9y = 1 \\ 9y = 9 \\ y = 1$

Ответ: (2;-3), (-2;1)