Question

Tìm n biết :

a) \(3⋮\left(n+5\right)\)

b) \(\left(-3n+2\right)⋮\left(2n+1\right)\)

Answer 1

a) 3 \(⋮\) n+5

\(\Rightarrow n+5\inƯ\left(3\right)=\left\{1;3;-1;-3\right\}\)

\(\Rightarrow n\in\left\{-4;-2;-6;-8\right\}\)

Vậy.....................................

Answer 2

a: =>\(n+5\in\left\{1;-1;3;-3\right\}\)

=>\(n\in\left\{-4;-6;-2;-8\right\}\)

b: =>-6n+4 chia hết cho 2n+1

=>-6n-3+7 chia hết cho 2n+1

=>\(2n+1\in\left\{1;-1;7;-7\right\}\)

=>\(n\in\left\{0;-1;3;-4\right\}\)