Question

(Urca-CE) O número raiz cubica de {[(3^15)+(3^14)+(3^13)]/39} é igual a : 
Resposta: 81 

Answer 1

$\sqrt[3]{\frac{3^{15}+3^{14}+3^{13}}{39}} = \sqrt[3]{\frac{9.3^{13}+3.3^{13}+3^{13}}{39}}= \sqrt[3]{\frac{13.3^{13}}{39}}= \sqrt[3]{\frac{3^{13}}{3}}= \sqrt[3]{3^{12}}=3^4=81$