a, \(3n-3\ne0\Leftrightarrow3n\ne3\Leftrightarrow n\ne1\)
b, Đê B nguyên thì:
\(5n+2⋮3n-3\Rightarrow15n+6⋮3n-3\Leftrightarrow15n+6-5\left(3n-3\right)⋮3n-3\Leftrightarrow21⋮3n-3\Leftrightarrow3n-3\in\left\{21;-21;-3;3\right\}\Leftrightarrow3n\in\left\{24;-18;0;6\right\}\Leftrightarrow n\in\left\{8;-6;0;2\right\}\)