Question

СРООООООЧНООООООООООО!!!! ДАЮ 80 БАЛЛОВ

Answer 1

$\displaystyle\bf\\\left \{ {{5x + 3y = 7 \: \: | \times 2} \atop { - 2x + 4y = - 8 \: \: | \times 5 }} \right. \\ \displaystyle\bf\\ + \left \{ {{10x + 6y = 14} \atop { - 10x + 20y = - 40 }} \right. \\ \\ 6y + 20y = 14 - 40 \\ 26y = - 26 \\ y = - 6 \div 26 \\ y = - 1 \\ \\ 5x + 3 \times ( - 1) = 7 \\ 5x - 3 = 7 \\ 5x = 7 + 3 \\ 5x = 10 \\ x = 10 \div 5 \\ x = 2$

Ответ: ( 2 ; - 1 )

Answer 2

Ответ:

(2; -1)

Объяснение:

{5х + 3у = 7

{-2х + 4у = -8 | * 2,5

{5х + 3у = 7

{-5х + 10у = -20

{13у = -13

{5х + 3у = 7

1)

13у = -13

у = -13 : 13

у = -1

2)

5х + 3у = 7

5х + 3 * (-1) = 7

5х - 3 = 7

5х = 7 + 3

5х = 10

х = 10 : 5

х = 2