Question

va rog ajutatima dau coroana​

Answer 1

Explicație pas cu pas:

$A = {7}^{n + 2} \cdot {2}^{n + 1} + {7}^{n + 1} \cdot {2}^{n + 2} - {7}^{n} \cdot {2}^{n} \\ = {7}^{n} \cdot {2}^{n} \cdot ({7}^{2} \cdot 2 + 7 \cdot {2}^{2} - 1) \\ = {(7 \cdot 2)}^{n} \cdot (49 \cdot 2 + 7 \cdot 4 - 1) \\ = 125 \cdot {14}^{n} = 5 \cdot 25 \cdot {14}^{n} \bf \ \ \vdots \ \ 25$

q.e.d.