Question

Am un numar de 6 cifre.Daca ii punem la stanga cifra 3 obtinem dublul numarului in care am pus la dreapta cifra 7.Aflati numarul?

Answer 1

[tex]Notam\ x=\overline{a_1a_2a_3a_4a_5a_6}\\ \overline{3a_1a_2a_3a_4a_5a_6}=2\cdot \overline{a_1a_2a_3a_4a_5a_67}\\ 3000000+\overline{a_1a_2a_3a_4a_5a_6}=2\cdot(10\cdot \overline{a_1a_2a_3a_4a_5a_6}+7)\\ 3000000+x=2\cdot(10\cdot x+7)\\ 3000000+x=20\cdot x+14\\ 2999986=19x\\ x=157894=\overline{a_1a_2a_3a_4a_5a_6}\\ Verificare\\ 3157894=2\cdot 1578947\\[/tex]