Решите систему уравнений.
2 (3x + 2y) - 4x-21=-9.
3 - (6x + 5y) = 2x+ 10.​

{2(3x + 2y) + 9 = 4x + 21,

2x + 10 = 3 - (6x + 5y);

{6x + 4y + 9 = 4x + 21,

2x + 10 = 3 - 6x - 5y;

{2x + 4y = 12,

8x + 5y = -7;

{x + 2y = 6,

8x + 5y = -7;

{ x = 6 - 2y,

8 * (6 - 2y) + 5y = -7;

{ x = 6 - 2y,

48 - 16y + 5y = -7;

{ x = 6 - 2y,

-11y = - 55;

{ x = 6 - 2y,

y = 5;

{ x = 6 - 2 * 5,

y = 5;

{ x = -4,

y = 5.

ответ: (-4; 5).

Объяснение: