Question

3 la puterea n+2+7x3 la puterea n+3-5x3 la puterea n+1.

Answer 1

 [tex]3^{n+2}+7\cdot3^{n+3}-5\cdot3^{n+1}=\\ =3^{n+1}\cdot(3+7\cdot3^2-5)=3^{n+1}\cdot(3+63-5)=3^{n+1}\cdot61[/tex]