Question

решите систему линейных уравнений {x+y=7 ;
{5x-7y=11,

Answer 1

$left { {{x=7-y} atop {5*7-5y-7y=11}} right.$
$left { {{x=7-y} atop {35-12y=11}} right.$
$left { {{x=7-y} atop {-12y=-24}} right.$
$left { {{x=5} atop {y=2}} right.$