Question

Помогите сделать номер 974

Answer 1

$1) \ \ x - 2y = -8 \ \ x) \ \ x = 2y - 8 \ \ y) \ \ -2y = -8 -x \ \ y = frac{-8-x}{2} \ \ 2) \ \ 7x - y = 9 \ \ x) \ \ 7x = 9 + y \ \ x = frac{9+y}{7} \ \ y) \ \ y = 7x - 9 \ \ 4) \ \ 5x - 7y = 12 \ \ x) \ \ 5x = 12 + 7y \ \ x = frac{12+7y}{5} \ \ y) \ \ -7y = 12 - 5x \ \ y = frac{12-5x}{-7}$