4x+8y=-4 dan 3x-6y=21

4x+8y = -4 x3
3x-6y = 21 x4
______________ +
12x + 24 y = -12
12x - 24 y = 84
-> 24 x = 72
x = 3
4.3+ 8y = -4
12 + 8y = -4
8y = -16
y = -2