a+b+c=7887
a+b=4533
b+c=4878
Avem: b+c=4878 si ne ducem in relatia a+b+c=7887 (inlocuim b+c)
a+4878=7887
a=7887-4878=3009
Avem: a+b=4533
3009+b=4533
b=4533-3009
b=1524
Avem: a+b+c=7887 si a+b=4533 atunci => c=7887-4533=3354
Proba: a+b+c=3009+1524+3354=7887