\begin{tikzpicture}
\begin{axis}[
name=plot1,
axis equal,
axis lines*=middle,
enlargelimits = false, clip=true,
xmin=-1.39,
xmax=1.39,
ymin=-1.10,
ymax=1.10,
axis line style={->,>=stealth},
xlabel={$\mathrm{Re}\{z\}$},
ylabel={$\mathrm{Im}\{z\}$},
every axis x label/.style={
at={(ticklabel* cs:1)},
anchor=north,
},
every axis y label/.style={
at={(ticklabel* cs:1)},
anchor=south,
},
xtick=1, ytick=\empty,
xticklabel style={xshift=0.1cm},
every outer y axis line/.append style={white!15!black},
every y tick label/.append style={font=\color{white!15!black}},
legend style={draw=white!15!black,fill=white,legend cell align=left}]
\draw (axis cs:0,0) circle [black!50, dashed, line width=2pt, radius=1];
\if\SOLUTIONS1
	\addplot [line width=1pt,mark=x, only marks, mark size = 3pt]
	table[row sep=crcr]{
		0.56569 0.56569 \\
		0.56569 -0.56569 \\
	};
	
	\addplot [line width=1pt,mark=*, only marks, mark size = 3pt, mark options={fill=white}]
	table[row sep=crcr]{
		-0.88388 0.88388 \\
		-0.88388 -0.88388 \\
	};
\fi
\end{axis}

\begin{axis}[
name=plot2,
at= (plot1.east), anchor=west, xshift=1cm,
%at=(plot1.below south east), anchor=above north east,
axis equal,
axis lines*=middle,
enlargelimits = false, clip=true,
xmin=-1.39,
xmax=1.39,
ymin=-1.10,
ymax=1.10,
axis line style={->,>=stealth},
xlabel={$\mathrm{Re}\{z\}$},
ylabel={$\mathrm{Im}\{z\}$},
every axis x label/.style={
	at={(ticklabel* cs:1)},
	anchor=north,
},
every axis y label/.style={
	at={(ticklabel* cs:1)},
	anchor=south,
},
xtick=1, ytick=\empty,
xticklabel style={xshift=0.1cm},
every outer y axis line/.append style={white!15!black},
every y tick label/.append style={font=\color{white!15!black}},
legend style={draw=white!15!black,fill=white,legend cell align=left}]
\draw (axis cs:0,0) circle [black!50, dashed, line width=2pt, radius=1];
\if\SOLUTIONS1
  \addplot [\SolutionsColor, line width=1pt,mark=x, only marks, mark size = 3pt]
  table[row sep=crcr]{
      0.56569 0.56569 \\
      0.56569 -0.56569 \\
      0.8839 +0.8839 \\
      0.8839 -0.8839 \\
  };

  \addplot [\SolutionsColor, line width=1pt,mark=*, only marks, mark size = 3pt, mark options={fill=white}]
  table[row sep=crcr]{
      -0.88388 0.88388 \\
      -0.88388 -0.88388 \\
      -0.5657 +0.5657 \\
      -0.5657 -0.5657  \\
  };
\fi
\end{axis}

\node[below] at (plot1.south) {(a)};
\node[below] at (plot2.south) {(b)};
\end{tikzpicture}