Question

(3n-1) chia hết cho n+2

(5n+3) chia hết cho (2n+1)

(3-n mũ 2 ) chia hết cho n-1

Answer 1

\\la cai chich me may

Answer 2

\(3n-1⋮n+2\)

\(\Rightarrow3n+6-7⋮n+2\)

\(\Rightarrow3\left(n+2\right)-7⋮n+2\)

Do : \(3\left(n+2\right)⋮n+2\)suy ra : \(7⋮n+2\)

\(\Rightarrow n+2\inƯ\left(7\right)=\left\{-7;-1;1;7\right\}\)

\(\Rightarrow n\in\left\{-9;-3;-1;5\right\}\)

Answer 3

3n - 1 = 3n + 6 - 7 = 3(n + 2) - 7

Để \(\left(3n-1\right)⋮\left(n+2\right)\) thì \(7⋮\left(n+2\right)\)

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

Nếu n + 2 = -7 => n = -7 - 2 => n = -9

Nếu n + 2 = -1 => n = -1 - 2 => n = -3

Nếu n + 2 = 1 => n = 1 - 2 => n = -1

Nếu n + 2 = 7 => n = 7 - 2 => n = 5

Vậy \(n\in\left\{-9;-3;-1;5\right\}\)

Answer 4

a)( 3n - 1 ) \(⋮\)n + 2  \(\Rightarrow\) 3(n+2)\(⋮\)n+2   => 3n+4 \(⋮\) n+2

=>  3n+4  -  3n-1  \(⋮\)n+2

3\(⋮\)n+2

n+2	1	3
n	-1	1

vậy n = -1 : 1

b) 5n+3\(⋮\)2n+1 => 2(5n+3) - 5(2n+1)\(⋮\)2n+1

10n+3-10n+5 \(⋮\)2n+1

2 chia hết 2n+1

2n+1	1	2
n	0	loại

vậy n = 0

Answer 5

c) (3-n\(^2\))\(⋮\)n-1