Question

Решите систему уравнений . -x+2y=10
3y+x=25

Answer 1

$\left\{\begin{array}{l}-x+2y=10\\3y+x=25\end{array}\right\ \oplus \ \left\{\begin{array}{l}x=2y-10\\5y=35\end{array}\right\ \ \left\{\begin{array}{l}x=2\cdot 7-10\\y=7\end{array}\right\ \ \left\{\begin{array}{l}x=4\\y=7\end{array}\right\\\\\\Otvet:\ \ (4;7)\ .$

Answer 2

(4; 7)

Объяснение:

$- x + 2y = 10 \\ 3y + x = 25 \\ - x + 2y + (3y + x) = 10 + 25 \\ - x + 2y + 3y + x = 35 \\ 5y = 35 \\ y = 7$

$- x + 2 \times 7 = 10 \\ - x = 10 - 14 \\ - x = - 4 \\ x = 4$

Удачи☘.