Question

помогите решить. Даю 30 баллов! ​

Answer 1

$x + 2y = 0 \ 2x - y = 5 : : : | times 2 \ \ x + 2y = 0 \ 4x - 2y = 10 \ \ 5x = 10 \ x = 10 div 5 \ x = 2 \ \ 4 times 2 - 2y = 10 \ 8 - 2y = 10 \ 2y = 8 - 10 \ 2y = - 2 \ y = - 2 div 2 \ y = - 1 \ \ Ответ: :(2 : ; - 1: )$

$x - 6y = 15 \ 4x + 3y = 6 \ \ x = 15 + 6y \ 4(15 + 6y) + 3y = 6 \ \ 4(15 + 6y) + 3y = 6 \ 60 + 24y + 3y = 6 \ 27y = 6 - 60 \ 27y = - 54 \ y = - frac{54}{27} \ y = - 2 \ \ x = 15 + 6y = 15 + 6 times ( - 2) = 15 - 12 = 3 \ \ Ответ: :( 3 : ; : - 2 )$

$4x + 5y = 3 : : : | times ( - 5) \ 5x + 7y = 0 : : : | times 4 \ \ - 20x - 25y = - 15 \ 20x + 28y = 0 \ \ 3y = - 15 \ y = - frac{15}{3} \ y = - 5 \ \ 4x + 5 times ( - 5) = 3 \ 4x - 25 = 3 \ 4x = 3 + 25 \ 4x = 28 \ x = frac{28}{4} \ x = 7 \ \ Ответ: : ( 7 : ; : - 5)$

Answer 2

Ответ в приложенном фото )