Объяснение:
x +2 y = 4 / ×2
3x -4 y =2
2x + 4y =8
3 x - 4 y = 2 ( -4 х и +4 х сократим )
5x = 10
x = 2
2. 2х +7 у =11
4x- y = 7 / ×7
30 x = 60
x = 2
3. 3x +y = 4 / ×2
5x -2y = 14
6 x +2y = 8
5x -2y = 14
11x = 22
x=2
4. 7x - 4y = 2 / × 11
5x + 11y = 43 × 4
77x - 44y = 22
20 x + 44y = 172
97 x = 194
x = 2