Question

Giúp mik nhé cần gấp

Answer 1

Ta có: \(n^2-7⋮n+3\)

\(\Leftrightarrow n^2-9+2⋮n+3\)

mà \(n^2-9⋮n+3\)

nên \(2⋮n+3\)

\(\Leftrightarrow n+3\inƯ\left(2\right)\)

\(\Leftrightarrow n+3\in\left\{1;-1;2;-2\right\}\)

hay \(n\in\left\{-2;-4;-1;-5\right\}\)

Vậy: \(n\in\left\{-2;-4;-1;-5\right\}\)

Answer 2

Lời giải:

$n^2-7\vdots n+3$

$\Leftrightarrow n^2-9+2\vdots n+3$

$\Leftrightarrow (n-3)(n+3)+2\vdots n+3$

$\Leftrightarrow 2\vdots n+3$

$\Rightarrow n+3\in\left\{\pm 1;\pm 2\right\}$

$\Rightarrow n\in\left\{-4;-2;-1;-5\right\}$