Question

Tìm số nguyên n biết:

\(n-1\) là ước của -9

Answer 1

\(n-1\inƯ\left(-9\right)\)

\(\Rightarrow n-1=Ư\left(-9\right)=\left\{\pm1;\pm3;\pm9\right\}\)

\(\Rightarrow n=\left\{\begin{matrix}n-1=1\Rightarrow n=1+1=2\\n-1=3\Rightarrow n=3+1=4\\n-1=9\Rightarrow n=9+1=10\end{matrix}\right.\)

\(\Rightarrow n=\left\{\begin{matrix}n-1=-1\Rightarrow n=-1+1=0\\n-1=-3\Rightarrow n=-3+1=-2\\n-1=-9\Rightarrow n=-9+1=-8\end{matrix}\right.\)

\(\Rightarrow n=\left\{-8;-2;0;2;4;10\right\}\)