Răspuns :
x+y=130
x+z=100
y+z=70
2x+2y+2z=300
2(x+y+z)=300
x+y+z=300:2=150
x+y=130
z=150-130=20
x+z=100
x+20=100
x=100-20=80
y+z=70
y+20=70
y=70-20=50
80+50+20=150(verificare)
x+z=100
y+z=70
2x+2y+2z=300
2(x+y+z)=300
x+y+z=300:2=150
x+y=130
z=150-130=20
x+z=100
x+20=100
x=100-20=80
y+z=70
y+20=70
y=70-20=50
80+50+20=150(verificare)