Question

х+4у=7 x-2y = -5 дам 40 баллов

Answer 1

$left { {{x+4y=7} atop {x-2y=-5}} right. \\ x = 2y-5\ 2y-5+4y = 7\ 6y = 12\ y = 2\ x = 2y-5 = -1$

Answer 2

{x+4y=7
{x-2y=-5/*2⇒2x-4y=-10
прибавим 3x=-3
x=-1
-1+4y=7
4y=8
y=2
(1;2)