Systeme 和 Tikzmark

Question

以下程序输出下图。我的问题是：我可以改进这个程序以获得更精确的图像吗？节点不是计算出来的，而是通过反复试验得到的。有什么想法可以让程序代替我进行计算吗？

\documentclass{article}
\usepackage{tikz,amsmath}
\usepackage{systeme}
\usetikzlibrary{tikzmark}

\begin{document}

\hspace{2cm}\systeme{x+y=2 @\textcolor{red}{(1)}, 
\tikzmarknode{A}{}x-y\tikzmarknode{C} 
    {}=8\phantom{0}\tikzmarknode{B}{} @\textcolor{red}{(2)}}

\begin{tikzpicture}[overlay,remember picture]
%%%First Line
\node at ([yshift=-3ex]A.south) {$2x$};
\node at ([xshift=1.75ex,yshift=-3ex]C.south) {$=$};
\node at ([xshift=-1ex,yshift=-3ex]B.south) {$10$};
%%%Second Line
\node at ([xshift=-.75ex,yshift=-6.5ex]C.south) {$x$};
\node at ([xshift=1.75ex,yshift=-6.5ex]C.south) {$=$};
\node at ([xshift=-1.25ex,yshift=-6.5ex]B.south) {$5$};
%%%Draws line    
\draw[-,black,semithick] ([yshift=-6pt]A.south) to 
      ([yshift=-6pt]B.south);
\end{tikzpicture}   

\end{document}

Answer 1

如果你真的想走这条路，那么你可能想要使用systeme使用全部对齐，和 Ti钾Z 表示支撑和水平线。（最让我吃惊的是，它systeme并没有被\tikzmarknodes 搞糊涂。）

\documentclass{article}
\usepackage{tikz,amsmath}
\usepackage{systeme}
\usetikzlibrary{tikzmark,decorations.pathreplacing,calligraphy}
\begin{document}
\sysdelim..\hspace{2cm}\systeme{\tikzmarknode{x1}{x}+y=2 @\textcolor{red}{(1)}, 
\tikzmarknode{x2}{x}-y=8@\textcolor{red}{(2)},
\tikzmarknode{2x}{2x}=\tikzmarknode{10}{10},x=5}

\begin{tikzpicture}[overlay,remember picture]
 \draw[decoration={calligraphic brace,raise=0.2em}, decorate, line
 width=0.1em] ([yshift=-0.2em]x2.south west) -- ([yshift=0.3em]x1.north west);
 \path (x2) -- (2x) coordinate[pos=0.65](aux);
 \draw[very thick] (2x.west|-aux) -- (10.east|-aux);
\end{tikzpicture}   
\end{document}