Ops

\documentclass{standalone}
\usepackage{tikz,pgfplots}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
    scale only axis,,
    grid=major,
    unit vector ratio=1 1 1,
    enlargelimits=true,
    grid style={dashed, gray!30},
    axis lines=middle,
    inner axis line style={-stealth},
    xlabel={\large $x$},
    ylabel={\large $y$},
    legend style={cells={anchor=west}},
    yticklabel style={inner ysep=0pt, anchor=south east},
    ytick={-3,-2,...,5},
    xticklabel style={inner xsep=0pt, anchor=north west},
    xtick={-8,-7,...,6},
    ymin=-3.5,
    ymax= 5.5,
    xmin=-7.5,
    xmax= 6.5,
after end axis/.code={
        \path (axis cs:0,0)
            node [anchor=north west,yshift=-0.075cm] {0}
            node [anchor=south east,xshift=-0.075cm] {0};
    }
]
\addplot[color=black,fill=red,only marks] coordinates{
(-3,-2)
(6,3)
(2,4)};
\addplot[color=black,dashed,fill=green,fill opacity=.20,mark=none] coordinates{
(-3,-2)
(6,3)
(2,4)
(-7,-1)
(-3,-2)};
\addplot[color=black,fill=blue,only marks] coordinates{
(-7,-1)
(1,-3)};
\end{axis}
\end{tikzpicture}
\end{document}