Đáp án:
c) \(\left[ \begin{array}{l}
n = 8\\
n = - 10\\
n = 2\\
n = - 4\\
n = 0\\
n = - 2
\end{array} \right.\)
Giải thích các bước giải:
\(\begin{array}{l}
a)5n \vdots - 2\\
\Leftrightarrow n \in B\left( 2 \right)\\
\to \left[ \begin{array}{l}
n = 2\\
n = 4\\
n = 6\\
n = 8\\
n = 10\\
...
\end{array} \right.\\
b)8 \vdots n\\
\Leftrightarrow n \in U\left( 8 \right)\\
\to \left[ \begin{array}{l}
n = 8\\
n = - 8\\
n = 4\\
n = - 4\\
n = 2\\
n = - 2\\
n = 1\\
n = - 1
\end{array} \right.\\
c)9 \vdots n + 1\\
\to n + 1 \in U\left( 9 \right)\\
\to \left[ \begin{array}{l}
n + 1 = 9\\
n + 1 = - 9\\
n + 1 = 3\\
n + 1 = - 3\\
n + 1 = 1\\
n + 1 = - 1
\end{array} \right. \to \left[ \begin{array}{l}
n = 8\\
n = - 10\\
n = 2\\
n = - 4\\
n = 0\\
n = - 2
\end{array} \right.\\
d)n - 18 \vdots 17\\
\to n - 1 - 17 \vdots 17\\
\to n - 1 \vdots 17\\
\to n - 1 \in B\left( {17} \right)\\
\to \left[ \begin{array}{l}
n - 1 = 17\\
n - 1 = 34\\
n - 1 = 51\\
...
\end{array} \right.\\
\to \left[ \begin{array}{l}
n = 18\\
n = 35\\
n = 52\\
...
\end{array} \right.
\end{array}\)
