Question

tìm số nguyên n

a) n+ 7 chia hết n+2

b) 9- n chia hết n-3

c) \(n^{^2}\) +n +17 chia hết n+1

d) \(n^{^2}\) +25 chia hết n +2

e)2n+7 chia hết n+1

g) 3\(n^{^2}\)+5 chia hết n-1

h) 3n+7 chia hết 2n +1

i) 2\(n^{^2}\) +11 chia hết 3n +1

Answer 1

a: \(\Leftrightarrow n+2+5⋮n+2\)

\(\Leftrightarrow n+2\in\left\{1;-1;5;-5\right\}\)

hay \(n\in\left\{-1;-3;3;-7\right\}\)

b: \(\Leftrightarrow n-3-6⋮n-3\)

\(\Leftrightarrow n-3\in\left\{1;-1;2;-2;3;-3;6;-6\right\}\)

hay \(n\in\left\{4;2;5;1;6;0;9;-3\right\}\)

c: \(\Leftrightarrow17⋮n+1\)

\(\Leftrightarrow n+1\in\left\{1;-1;17;-17\right\}\)

hay \(n\in\left\{0;-2;16;-18\right\}\)