Question

5x+y=7
7x-4y=-1
Помогите решить

Answer 1

$5x + y = 7 \\ 7x - 4y = - 1 \\ \\ 20x + 4y = 28 \\ 7x - 4y = - 1 \\ \\ 27x = 27 \\ y = 7 - 5y \\ \\ x = 1 \\ y = 2$
Ответ: (1; 2)

Answer 2

{ 5x + y=7
{ 7x -4y = -1

{ y = 7-5x
{ 7x - 4y = -1

7x -4(7-5x) = -1

x = 1

y = 7-5*1

y =2

(x, y) = (1, 2)

{ 5*1 + 2 = 7
{ 7 * 1 -4 *2 = -1

{ 7 = 7
{ -1 = -1

ОТВЕТ::: (1; 2)