{2x+4z=8600 inmultim -1
{2y+4z=9600
{-2x-4z=-8600
{2y+4z=9600
2y-2x+4z-4z=9600-8600
2y-2z=1000
{2y-2x=1000
{2y+2x=1400
2y+2y-2x+2x=1400+1000
4y=2400
y=2400/4
y=600 de gaste
din 2y-2x=1000 :2
y-x=500
x=y-500=600-500
x=100 de gaini
din 2x+4z=8600 :2
x+2z=4300
2z=4300-x
2z=4300-100
2z=4200
z=4200/2
z=2100 de oi
verificare
2y+2x=1400
2·600+2·100=1400
1200+200=400