Question

Aflati numerele naturale de forma abc, stiind ca abc-ab-c=486

Answer 1

abc-ab-c=486
100a+10b+c-10a-b-c=486
90a+9b=486
9(10a+b)=486
numarul de forma ab=486:9=54
deci a=5, b=4
abc-c=486+54
abc-c=540
atunci c poate avea valori de la 0 la 9
deci numarul de forma abc poate fi: 540, 541, 542, 543, 544, 545, 546, 547, 548, 549

Answer 2

adica ... 100a+10b+c - (10a+b) - c = 486

      ⇒     90a + 9b = 486   | : 9

                                           __

                10a+b = 54  ⇔   ab = 54  iar c = {0;1;2;3;4;5;6;7;8;9}

      ⇒     ___

              abc  = {540;541;542;543;544;545;546;547;548;549}