Question

Решите систему уравнений 3x - 5y = 9, 4x + 5y = 12

Answer 1

3x - 5y = 9

{

4x + 5y = 12

3x - 5y = 9

+

4x + 5y = 12

1) 7х = 21 | :7

х=3

2) 4*3+5у=12

12+5у=12

5у=12-12

5у=0 | :5

у=0

Ответ: (3;0)