a, 2008\(-⋮\)-1(mod 2009)
\(2008^{100}-⋮1\left(mod2009\right)\)
\(2008^{99}-⋮-1\left(mod2009\right)\)
=>\(2008^{100}+2008^{99}⋮2009\)
b,\(12345-⋮1\left(mod12344\right)\)
\(12345^{678}-⋮1\left(mod12344\right)\)
\(12345^{677}-⋮1\left(mod12344\right)\)
\(12345^{678}+12345^{677}không⋮12344\)(đề sai)
\(-⋮\)là đồng dư nha