Question Number 10577 by pan123 last updated on 19/Feb/17
$$\mathrm{5}^{\mathrm{71}} +\mathrm{5}^{\mathrm{72}} +\mathrm{5}^{\mathrm{73}} =? \\ $$
Answered by ridwan balatif last updated on 19/Feb/17
$$\mathrm{5}^{\mathrm{71}} +\mathrm{5}^{\mathrm{72}} +\mathrm{5}^{\mathrm{73}} \\ $$$$=\mathrm{5}^{\mathrm{71}} \left(\mathrm{1}+\mathrm{5}+\mathrm{5}^{\mathrm{2}} \right) \\ $$$$=\mathrm{5}^{\mathrm{71}} ×\mathrm{31} \\ $$