Question

afla toate nr naturale de forma abc in care 4a+b+c=12.

Answer 1

abc; 4a+b+c=12, a e diferit de 0
daca a=1,12-4x1=8(suma ultimelor doua cifre b+c), numerele sunt:
417,426,435,453,462,471,408, 480;
daca a=2 avem 12-4x2=12-8=4( b+c=4), atunci numerele sunt:
804, 813,831,840.