Question

метод подстановки -х+2у=4 7х-3у=5

Answer 1

Х=2y-4; 7(2y-4)-3y=5; 14y-28-3y=5; 11y=33;y=3; x=6-4=2 Ответ:(2;3)

Answer 2

$left { {{-x+2y=4} atop {7x-3y=5}} right. \ left { {{-x=4-2y} atop {7x-3y=5}} right. \ left { {{x=-4+2y} atop {7x-3y=5}} right. \ left { {{x=-4+2y} atop {7(-4+2y)-3y=5}} right. \ 7(-4+2y)-3y=5 \ -28+14y-3y=5 \ -28+11y=5 \ 11y=33 \ y=3 \ \ x=-4+2y \ x=-4+2*3 \ x=2 (2;3)$