我正在尝试生成此文件，但出现错误 pdflatex-halt-on-error-inter...我添加了包 \usepackage{graphicx}，但它不起作用，有什么想法吗？
\documentclass[12pt]{article}
\usepackage{amsmath,amsthm, amssymb, latexsym}
\usepackage{tikz}
\makeatletter
\renewcommand*\env@matrix[1][c]{\hskip -\arraycolsep
\let\@ifnextchar\new@ifnextchar
\array{*\c@MaxMatrixCols #1}}
\makeatother
\usepackage{moodle}
\usetikzlibrary{external} % set this
\tikzexternalize % explicitly
\usepackage{graphicx}
\begin{document}
\begin{quiz}{Revisiting Linear Algebra}
\begin{multi}[points=2]{Matrix Form of a Linear System}
Consider the following system
\begin{tikzpicture} % matrix inside of tikzpicture node
\node{
$\begin{matrix}[r]
3.0 x_1 &+2.0 x_2 &+2.0 x_3 & -5.0 x_4 & =8 .0 \\
0.6 x_1 &+ 1.5 x_2 &+1.5 x_3 & -5.4 x_4 & =2.7 \\
1.2 x_1 & -0.3 x_2 & -0.3 x_3 & 2.4 x_4 & =2.1 , \\
\end{matrix}
$};
\end{tikzpicture}
which may be written as a single vector equation; i.e, $\mathbf{AB}=\mathbf{B}$.\\
The $\mathbf{A}$ matrix associated with the system is:
\item*
\begin{tikzpicture}
\node{ $
\begin{bmatrix}[r]
3.0 &+2.0 &+2.0 & -5.0 \\
0.6 &+ 1.5 &+1.5 & -5.4 \\
1.2 & -0.3 & -0.3 & 2.4 , \\
\end{bmatrix}
$};\end{tikzpicture}
\item\begin{tikzpicture}
\node{ $
\begin{bmatrix}[r]
8 .0 \\
2.7 \\
2.1 \\
\end{bmatrix}
$};\end{tikzpicture}
\item \begin{tikzpicture}
\node{$
\begin{bmatrix}[r]
x_1 &\\
x_2& \\
x_3 &\\
x_4 &\\
\end{bmatrix}
$};\end{tikzpicture}
\item
\begin{tikzpicture}
\node{$
\begin{bmatrix}[r]
3.0 &+2.0 &+2.0 & -5.0 & 8.0 \\
0.6 &+ 1.5 &+1.5 & -5.4 & 2.7 \\
1.2 & -0.3 & -0.3 & 2.4 , & 2.1\\
\end{bmatrix}
$};
\end{tikzpicture}
\end{multi}
\end{quiz}
\end{document}