Question

Розвʼяжіть систему способом додавання
-5х+3у=27,
5х+2у=-7;

Answer 1

$\displaystyle\bf\\ + \left \{ {{ - 5x + 3y = 27} \atop {5x + 2y = - 7 }} \right. \\ \\ 3y + 2y = 27 - 7 \\ 5y = 20 \\ y = 20 \div 5 \\ y = 4 \\ \\ 5x + 2 \times 4 = - 7 \\ 5x + 8 = - 7 \\ 5x = - 7 - 8 \\ 5x = - 15 \\ x = - 15 \div 5 \\ x = - 3$

Ответ: ( - 3 ; 4 )