1/2x+1/5y=-1 dan 1/4x-1/5y=-2

5x + 2y = -10 (sudah dikali 10)
5x - 4y = -40 (sudah dikali 20)
__________-
6y = 30
y = 5

5x - 4y = -40
5x - 4(5) = -40
5x - 20 = -40
5x = -40+20
5x = -20
x = -4

Jadi,
x = -4
y = 5

1/2 x + 1/5 y = -1
1/4 x - 1/5 y = -2
------------------------- +
3/4 x = -3
x = -3 x 4/3
x = -4

1/4(-4) - 1/5 y = -2
-1 -1/5 y = -2
-1/5 y = -2 + 1
-1/5 y = -1
y = -1 x (-5)
y= 5