Question

[Hoàng Mai Lê]

a) n² - 2n - 2 \(⋮\)n + 1

b) n² + 2n + 7 \(⋮\) n + 2

c) n² + 1 \(⋮\) n - 1

Answer 1

[Nguyễn Lê Phước Thịnh]

a: \(\Leftrightarrow n^2+n-3n-3+1⋮n+1\)

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

hay \(n\in\left\{0;-2\right\}\)

b: \(\Rightarrow n\left(n+2\right)+7⋮n+2\)

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

hay \(n\in\left\{-1;-3;5;-9\right\}\)

c: \(\Leftrightarrow n^2-1+2⋮n-1\)

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

hay \(n\in\left\{2;0;3;-1\right\}\)