documentclass[tikz,border=3.14mm]{standalone}
usetikzlibrary{arrows.meta,decorations.pathreplacing}
begin{document}
begin{tikzpicture}
 draw[stealth-stealth] (-6,0) node[below]{$-infty$} -- (6,0) node[below]{$infty$};
 draw foreach X in {-4,-3,...,4} {(X,.1) -- (X,-.1) node[below=0.2em]{$X$}};
 draw[very thick,red] (0,0.06) -- (4,0.06);
 draw[very thick,blue,{Bracket[reversed,width=1.2em]}-{Bracket[width=1.2em]}] (-3.05,0) -- (2,0) node[pos=1/5,above]{$I$};
 draw[very thick,red,{Bracket[width=1.2em]}-{Bracket[width=1.2em]}] (0,0) -- (4,0) node[pos=3/4,above]{$J$};
 draw[decorate,decoration=brace] (-3,0.5) -- (4,0.5) node[midway,above=0.1em]{$Icup J$};
end{tikzpicture}
begin{tikzpicture}
 draw[stealth-stealth] (-6,0) node[below]{$-infty$} -- (6,0) node[below]{$infty$};
 draw foreach X in {-4,-3,...,4} {(X,.1) -- (X,-.1) node[below=0.2em]{$X$}};
 draw[very thick,red] (0,0.06) -- (4,0.06);
 draw[very thick,blue,{Bracket[reversed,width=1.2em]}-{Bracket[width=1.2em]}] (-3.05,0) -- (2,0) node[pos=1/5,above]{$I$};
 draw[very thick,red,{Bracket[width=1.2em]}-{Bracket[width=1.2em]}] (0,0) -- (4,0) node[pos=3/4,above]{$J$};
 draw[decorate,decoration=brace] (0,0.5) -- (2,0.5) node[midway,above=0.1em]{$Icap J$};
end{tikzpicture}
end{document}