Question

{x+2y=7 {2x-y=4
какой ответ?

Answer 1

$left { {{x+2y=7} atop {2x-y=4}} right. x=7-2y; 2(7-2y)-y=4; 14-5y=4; 5y=10; y=2, x=3.$

Answer 2

думаю разберёшься)))