如何在数组中添加减法水平线

Question

我已经有了：

\documentclass{article}
\usepackage{amsmath}

\begin{document}    
$k:\left\{ \begin{array}{cccccc}x & = & -3+3\lambda & \Big| & 4 & \Big| \\ y & = & 4-4\lambda & \Big| & -3 & \Big| \end{array} \right. \Rightarrow \left\{ \begin{array}{cccccc}4x & = & -12+12\lambda \\ -3y & = & -12+12\lambda \end{array} \right.$
\end{document}

我有点想要这个：

获得减法线的最佳方法是什么？

Answer 1

\documentclass{article}
\usepackage{amsmath}

\begin{document}    

aaaaaa
\[\renewcommand\arraystretch{1.5}
k:\Biggl\{ \begin{array}{@{}cccccc}
x & = & -3+3\lambda \\
y & = & 4-4\lambda
\end{array}
\quad
\Biggl|\begin{array}{@{}r@{}}
4\\
  -3
\end{array}
\Biggr|
%
 \Rightarrow 
\Biggl\{ \begin{array}{@{}cccccc@{\qquad}l}
4x & = & -12+12\lambda \\ 
-3y & = & -12+12\lambda \\
\cline{1-3}
4x+3y&=&0&{}\Rightarrow x=-3/4 y\\
\noalign{\vspace{-1.5\normalbaselineskip}}
\end{array}
\]
\vspace{1.5\normalbaselineskip}
aaaa
\end{document}