Question

Решите систему уравнений :
{х-4у=7
{2х-у=7

Answer 1

$left { {{x-4y=7} atop {2x-y=7}} right. left { {{x-4y=7} atop {-8x+4y=-28}} right. left { {{x-4y=7} atop {-8x+4y=-28}} right. -7x=-21, x=3, left { {-4{y=7-3} atop {x=3}} right. left { {{y=-1} atop {x=3}} right.$

Ответ: (3;-1)