Question

Quanto e {-5x-y=12 x+y=-4

Answer 1

{-5x-y=12
{x+y=-4
x+y=-4.(5)
{-5x-y=12
{5x+5y=-20
4y=-8
y=-8/4
y=-2
5x+5y=-20
5x+5.(-2)=-20
5x-10=-20
5x=-20+10
5x=-10
x=-10/5
x=-2

Answer 2

-5x - y = 12
x + y  = 4                      x + y = 4
 ¨¨¨¨¨¨¨¨¨¨¨¨                       -4 +y = 4
 -4x  = 16                           y = 4 + 4
    x = 16 / -4                      y = 8
    x =  -4