Предмет: Математика, автор: apricotsocks

системы, с подробной росписью решения

Приложения:

iramazurk: Какой метод нужен?
iramazurk: Сложения или подстановки?

Ответы

Автор ответа: iramazurk
1

Ответ:

Пошаговое объяснение:

Приведём дроби к общему знаменателю и раскроем скобки:

Е)

3(х + 2у) - 6(х - 2у) - 4(7 - 2у) = 12(1 - х)

3х - 2у = 8

3х + 6у - 6х + 12у - 28 + 8у = 12 - 12х

3х - 2у = 8

-3х + 26у - 28 = 12 - 12х

3х - 2у = 8

-3х + 26у + 12х = 12 + 28

3х - 2у = 8

9х + 26у = 40

3х - 2у = 8

Решим систему методом сложения:

12х + 24у = 48 | : 12

3х - 2у = 8

х + 2у = 4

3х - 2у = 8

х = 4 - 2у

3х - 2у = 8

1)

3х - 2у =8

3(4 - 2у) - 2у = 8

12 - 6у - 2у = 8

-6у - 2у = 8 - 12

-8у = -4

у = -4 : (-8)

у = 4/8

у = 1/2

2)

х = 4 - 2у

х = 4 - 2*1/2

х = 4 - 2/2

х = 4 - 1

х = 3

Ответ: (3; 1/2)

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