Question

Помогите срочно!!!!! 1){2х-3у+1+(х-у+5)=0 {5х+7у-(8х+у+1)=0

Answer 1

$2x - 3y + 1 + (x - y + 5) = 0 \ 5x + 7y - (8x + y + 1) = 0 \ \ 2x - 3y + 1 + x - y + 5 = 0 \ 5x + 7y - 8x - y - 1 = 0 \ \ 3x - 4y + 6 = 0 \ - 3x + 6y - 1 = 0$

Складываем

$2y + 5 = 0 \ 2y = - 5 \ y = - 5 div 2 \ y = - 2.5 \ \ 3x - 4y + 6 = 0 \ 3x - 4 times ( - 2.5) + 6 = 0 \ 3x + 10 + 6 = 0 \ 3x + 16 = 0 \ 3x = - 16 \ x = - 16 div 3 \ x = - 5 frac{1}{3} \ \ otvet : ( - 5 frac{1}{3} : ; : - 2.5)$