Question

Решите лёгкую систему. (7 класс)

Answer 1

x = 10 + y

x – 2y + 2 = 4

x = 10 + y

x = 2 + 2y

(2y – y) + (2 – 10) = (x – x)

y – 8 = 0

y = 8

x = 10 + 8 = 18

Ответ: x = 18; y = 8.

Answer 2

$\displaystyle \begin{cases}x = 10 + y \\ x - 2y + 2 = 4 \end{cases} \\ \begin{cases}x - y = 10 \\ x - 2y = 2\!\mid\!\!\times ( - 1) \end{cases} \\ \begin{cases} x - y = 10 \\ - x + 2y = - 2 \end{cases} \\ \overline{ \qquad \qquad \qquad} \\ y = 8 \\ \overline{ \qquad \qquad} \\ x - 8 = 10 \\ x = 18$

Ответ: x=18; y=8