Inlocuim valorile:
x=700-y
z=500-y
Aflam cat inseamna y:
700-y+500-y=800
1200-2y=800
2y=400
y=200
Probam pentru a afla valorile celorlalte necunoscute:
x+y=700
x+200=700 => x=700-200=500
x=500
y+z=500
200+z=500 => z=500-200=300
z=300
x+z=800
500+300=800
