echilibram egalitatile adaugand a,b respectiv c, avem:
2a+2b+2c=90+c;2a+2b+2c=100+b;2a+2b+2c=110+a;
obtinem egalitatile:
90+c=100+b ->c-b=10;90+c=110+a ->c-a=20;100+b=110+a->b-a=10;b-a=10=>a=b-10;
a=110-2b-2c=110-2a-20-2a-40=50-4a=>5a=50 =>a=10, c=30,b=20;
Verificare:
20+60+30=90;20+20+60=100;10+40+60=110;
