Question

Chứng minh: 5²⁰⁰⁵ + 5²⁰⁰³ chia hết cho 13

Answer 1

\(5^{2005}+5^{2003}\)

\(=5^{2003}.\left(5^2+1\right)\)

\(=5^{2003}.26\)

\(=5^{2003}.2.13\)\(⋮\)\(13\)

Answer 2

5^2005 + 5^2003 = 5^2003 (5^2 +1)

                         = 5^2003 .26 chia hết cho 13

Answer 3

\(5^{2005}+5^{2003}=5^{2003}\left(5^2+1\right)=5^{2003}.26=5^{2003}.13.2⋮13\)

Answer 4

Sao rút ra lại có 5²+1 vậy?