Question

Stabiliti daca: a=4×3 2n+3 + 3 2n+2 + 3 2n+1
Se divide la 30

Answer 1

Scoatem factor comun $3^{3n+1}$

$a=3^{3n+1}(4*3^{2}+3+1)\\a=3^{3n+1}(36+3+1})\\a=3^{3n}*3*40\\a=3^{3n}*30*4$ ⇒ a este divizibil cu 30