Re: metodo di riduzione

ho voluto provare la libreria…
e non funziona nulla perché?

`
\documentclass[a4paper]{article}
\usepackage{amsmath,tikz}
\usetikzlibrary{positioning}
\usetikzlibrary{calc,tikzmark}
%\usetikzlibrary {tikzmark}
%\newcommand{\tikzmark}[1]{\tikz[remember picture,overlay,baseline=-.7ex]\node(#1){};}

\begin{document}
\[
\begin{cases}
3x+2y=2\\
\tikzmark{1}3x+3y=15\tikzmark{2}
\end{cases}\]
\begin{tikzpicture}[remember picture, overlay]
\node[below=0.1cm and 0cm of 1](3){};
\node[below=0.1cm and 0cm of 2](4){};
\node

(5){$3$};
\node[below right=0.2cm and 0cm of 5](6) {$0-y=-13$};
\draw (3) edge (4);% è la stessa cosa
\end{tikzpicture}

\end{document}
`
ciao
claudio