x+y+z=390450
x+y=188000 x=188000-y
y+z=272000 z=272000-y
acum inlocuim in ecuatie x si z
188000-y+y+272000-y=390450
460000-y=390450 y=460000-390450 y=69550
x+y=188000
x+69550=188000 x=188000-69550 x=118450
y+z=272000
69550+z=272000 z=272000-69550 z=202450
118450+69550+202450=390450
al 2-lea mod
390450-188000=202450
390450-272000=118450
390450-202450-118450=69550
202450+118450+69550=390450