Resposta :
{x + y = 6}
{2x - y = 6}
x + y = 6
x = 6 - y
2x - y = 6
2 . (6 - y) - y = 6
12 - 2y - y = 6
12 - 3y = 6
-3y = 6 - 12
-3y = -6
y = -6/-3
y = 2
x + y = 6
x + 2 = 6
x = 6 - 2
x = 4
{x + y = 6}
{2x - y = 6}
x + y = 6
x = 6 - y
2x - y = 6
2 . (6 - y) - y = 6
12 - 2y - y = 6
12 - 3y = 6
-3y = 6 - 12
-3y = -6
y = -6/-3
y = 2
x + y = 6
x + 2 = 6
x = 6 - 2
x = 4