Đáp án:
d. \(\left[ \begin{array}{l}
n = 8\\
n = 2
\end{array} \right.\)
Giải thích các bước giải:
\(\begin{array}{l}
a.n + 6 \vdots n\\
\Leftrightarrow 6 \vdots n\\
\to n \in U\left( 6 \right)\\
\to \left[ \begin{array}{l}
n = 6\\
n = 3\\
n = 2\\
n = 1
\end{array} \right.\\
b.n + 5 \vdots n + 1\\
\to n + 1 + 4 \vdots n + 1\\
\to 4 \vdots n + 1\\
\to n + 1 \in U\left( 4 \right)\\
\to \left[ \begin{array}{l}
n + 1 = 4\\
n + 1 = 2\\
n + 1 = 1
\end{array} \right.\\
\to \left[ \begin{array}{l}
n = 3\\
n = 1\\
n = 0
\end{array} \right.\\
c.4n + 5 \vdots n\\
\Leftrightarrow 5 \vdots n\\
\to n \in U\left( 5 \right)\\
\to \left[ \begin{array}{l}
n = 5\\
n = 1
\end{array} \right.\\
d.3n + 4 \vdots n - 1\\
\to 3\left( {n - 1} \right) + 7 \vdots n - 1\\
\to 7 \vdots n - 1\\
\to n - 1 \in U\left( 7 \right)\\
\to \left[ \begin{array}{l}
n - 1 = 7\\
n - 1 = 1
\end{array} \right.\\
\to \left[ \begin{array}{l}
n = 8\\
n = 2
\end{array} \right.
\end{array}\)
