X+2y=4

5x+8y=-1

4 х-у=4

5 х-2 у=11

9 х+2 у=16

3 х-5 у=11

Помогите

N 1

x + 2y = 4

x = 4 - 2y

5x + 8y = - 1

5• (4 - 2y) + 8y = - 1

20 - 10y + 8y = - 1

- 2y = - 21

y = 10,5

x = 4 - 2•10,5 = - 17

Ответ (- 17; 10,5)

N 2

4x - y = 4

y = 4x - 4

5x - 2y = 11

5x - 2• (4x - 4) = 11

5x - 8x + 8 = 11

- 3x = 3

x = - 1

y = - 4 - 4 = - 8

Ответ (- 1; - 8)

N 3

9x + 2y = 16

3x - 5y = 11

- 9x + 15y = - 33

17y = - 17

y = - 1

3x + 5 = 11

x = (11 - 5) : 3 = 2

Ответ (2; - 1)