Question

(7^2005+7^2004-7^2003):7^2002

 

Answer 1

7^2005 + 7^2004 - 7^2003 

= 7^2002 . 7^3 + 7^2002 . 7^2 - 7^2002 . 7^1

= 7^2002 . ( 7^3 + 7^2 - 7^1 ) chia hết cho 7^2002

Vậy 7^2005 + 7^2004 - 7^2003 chia hết cho 7^2002

Answer 2

Ta có:

\(\left(7^{2005}+7^{2004}-7^{2003}\right)\div7^{2002}\)

\(=\left(7^{2002}\cdot7^3+7^{2002}\cdot7^2-7^{2002}\cdot7\right)\div7^{2002}\)

\(=7^{2002}\left(7^3+7^2-7\right)\div7^{2002}\)

\(=7^3+7^2-7\)

\(=343+49-7\)

\(=385\)