Question

{2x - y = 0
{x + 2y = - 10

Answer 1

{2x-y=0
{x+2y=-10
x=-10-2y
2(-10-2y)-y=0
-20-4y-y=0
-4y-y=20
-5y=20.(-1)
5y=-20
y=-20/5
y=-4
x=-10-2y
x=-10-2.(-4)
x=-10+8
x=-2
S={(-2, -4)}

Answer 2

x = -10 - 2y

2(-10 - 2y) - y = 0
-20 - 4y - y = 0
-5y = 20
y = -4

x = -10 - 2y
x = -10 - 2(-4)
x = -10 + 8
x = -2

S = {(-2, -4)}

Espero ter ajudado.