\documentclass{article}
\usepackage{tkz-euclide} % coordinate plane
\begin{document}
\begin{tikzpicture}[scale=0.80]
\tkzInit[xmax=8,ymax=8,xmin=-8,ymin=-8]
\tkzGrid
\tkzAxeXY
% \draw[ very thick,dashed,latex-latex] (-6,4) -- (6,0);
\end{tikzpicture}
\end{document}