Question

решить систему способом подстановки
$x - 3y = 6 \\ 5x - 2y = 4$
​

Answer 1

Ответ:

(0; -2)

Пошаговое объяснение:

{х - 3у = 6

{5х - 2у = 4

{х = 6 + 3у

{5х - 2у = 4

1)

5х - 2у = 4

5(6 + 3у) - 2у = 4

30 + 15у - 2у = 4

15у - 2у = 4 - 30

13у = -26

у = -26 : 13

у = -2

2)

5х - 2у = 4

5х - 2 * (-2) = 4

5х + 4 = 4

5х = 4 - 4

5х = 0

х = 0 : 5

х = 0

Answer 2

$\displaystyle\bf\\\left \{ {{x - 3y = 6} \atop {5x - 2y = 4 }} \right. \\ \displaystyle\bf\\\left \{ {{x = 3y + 6} \atop {5(3y + 6) - 2y = 4 }} \right. \\ \\ 15y + 30 - 2y = 4 \\ 13y = 4 - 30 \\ 13y = - 26 \\ y = - 26 \div 13 \\ y = - 2 \\ \\ x = 3 \times( - 2) + 6 \\ x = - 6 + 6 \\ x = 0$

Ответ: ( 0 ; - 2 )