Question

A=15n+1+3*15n+3n+2*5n divizibil cu 27​

Answer 1

Explicație pas cu pas:

$A = {15}^{n + 1} + 3 \cdot {15}^{n} + {3}^{n + 2} \cdot {5}^{n} =$

$= 15 \cdot {15}^{n} + 3 \cdot {15}^{n} + 9 \cdot {(3 \cdot 5)}^{n}$

$= {15}^{n} \cdot (15 + 3 + 9) = 27 \cdot {15}^{n} \bf \ \ \vdots \ \ 27$

q.e.d.