$$\vcenter {\offinterlineskip
\def \cc#1{ \hfil #1 \hfil }
\halign {
\tvg \cc {$#$}& #\tv & \cc {$#$}&
\cc {$#$}& \cc {$#$}& \cc {$#$}& \cc{$#$} &#\tv\cr
\noalign {\hrule}
x&& -\infty&& 4&&+\infty&
\cr
\noalign {\hrule}
f'(x)&&& - & \doublevrule & +&&
\cr
\noalign {\hrule}
\buuucenter {$f(x)$} &&\bbuup {$0$}
&\bbrightddownarrow \down{$-\infty$} &\doublevrule &\down{$-\infty$}
~~ \bbrightuuparrow &\bbuup{8}&
\cr
\noalign {\hrule}
}}
$$