\(13^{101}-13=13\left(13^{100}-1\right)\)
Xét: \(169\equiv1\left(mod168\right)\Leftrightarrow169^{50}\equiv1\left(mod168\right)\Leftrightarrow13^{100}\equiv1\left(mod168\right)\)
\(\Leftrightarrow13^{100}-1\equiv0\left(mod168\right)\)<=>13100-1 chia hết cho 168
=>13(13100-1) chia hết cho 168=> đpcm