A/ \(13⋮\left(n+1\right)\Leftrightarrow\left(n+1\right)\inƯ\left(13\right)\)\(\Leftrightarrow\left(n+1\right)\in\left\{-13;-1;1;13\right\}\)\(\Leftrightarrow n\in\left\{-14;-2;0;12\right\}\)
KL: ...........................
B/ \(-5⋮\left(2n+3\right)\Leftrightarrow\left(2n+3\right)\inƯ\left(5\right)\)\(\Leftrightarrow\left(2x+3\right)\in\left\{-5;-1;1;5\right\}\)
\(\Leftrightarrow2n\in\left\{-8;-4;-2;2\right\}\)\(\Leftrightarrow n\in\left\{-4;-2;-1;1\right\}\)
KL: .....................