سلام
بصورت زیر:
\documentclass[12pt,a4paper]{report}
\usepackage{amsmath,enumerate}
\usepackage{enumitem}
\begin{document}
%%%%%%
\begin{enumerate}
\bfseries
\item[i)]
$x+y=z$
\item[ii)]
$x+y=z$
\item[iii)]
$x+y=z$
\end{enumerate}
%%%%%%
\begin{enumerate}[label=\textbf{\arabic*})]
\item
$x+y=z$
\item
$x+y=z$
\item
$x+y=z$
\end{enumerate}
%%%%%%%
\begin{enumerate}
\renewcommand\labelenumi{\bfseries\theenumi}
\item First item.
\item Second item.
\item Third item.
\end{enumerate}
\end{document}
خروجی:
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با استفاده از (description):
\documentclass[12pt,a4paper]{report}
\usepackage{amsmath}
\begin{document}
\begin{description}
\item[i)]
$x+y=z$
\item[ii)]
$x+y=z$
\item[iii)]
$x+y=z$
\end{description}
\end{document}
خروجی:
