\documentclass[12pt, a4paper]{article}
\usepackage[utf8]{vietnam}
\usepackage{amsmath,amsxtra,amssymb,latexsym, amscd,amsthm}
\usepackage[mathscr]{eucal}
\usepackage{tkz-tab} 
\usepackage[a4paper,left=1.5cm,right=1cm,top=1cm,bottom=1.5cm]{geometry}
\begin{document}

\begin{tikzpicture}
\tkzTabInit
{$x$ / .5}
{$a_1$ , $a_2$ , $a_3$}
\begin{scope}[arstyle/.style={>=latex,#1,<->}]
\draw[arstyle=blue] (N10) to node[above,color=blue]%
{\scriptsize $ espcl = 2$ cm} (N20);
\draw[arstyle=blue] (N20) to node[above,color=blue]%
{\scriptsize $ espcl = 2$ cm} (N30);
\draw[arstyle=red] (T10) to node[above=12pt,color=red]%
{\scriptsize $ deltacl = 0.5$ cm} (N10);
\draw[arstyle=red] (N30) to node[above=12pt,color=red]%
{\scriptsize $ deltacl = 0.5$ cm} (T20);
\draw[arstyle=blue] (T00) to node[above,color=blue]%
{\scriptsize $ lgt = 2$ cm} (T10);
\end{scope}
\end{tikzpicture}

\vspace{15pt}

\begin{tikzpicture}
\tkzTabInit[nocadre,lgt=1.5,espcl=2.5,deltacl=.5]
{$x$ /.7, $f'(x)$ /.7,$f(x)$ /2}
{$-\infty$ , $x_1$ , $x_2$ , $+\infty$}
\tkzTabLine{,+,z,-,z,+,}
\tkzTabVar{-/$-\infty$ ,+/ $f(x_1)$ ,-/$f(x_2)$, +/$+\infty$}
\end{tikzpicture}

\vspace{15pt}

\begin{tikzpicture}
\tkzTabInit[nocadre,lgt=1.5,espcl=2.5,deltacl=.5]
{$x$ /.7, $f'(x)$ /.7,$f(x)$ /2}
{$-\infty$ , $x_1$ , $x_2$ , $+\infty$}
\tkzTabLine{,-,z,+,z,-,}
\tkzTabVar{+/$+\infty$ ,-/ $f(x_1)$ ,+/$f(x_2)$, -/$-\infty$}
\end{tikzpicture}

\vspace{15pt}

\begin{tikzpicture}
\tkzTabInit[nocadre,lgt=1.5,espcl=2.5,deltacl=.5]
{$x$ /.7, $f'(x)$ /.7,$f(x)$ /2}
{$-\infty$ , $-x_0$ , $0$ , $x_0$ , $+\infty$}
\tkzTabLine{ ,-,z,+,z,-,z,+, }
\tkzTabVar{+/$+\infty$ ,-/ $f(x_0)$ ,+/$c$, -/$f(x_0)$,+/$+\infty$}
\end{tikzpicture}

\vspace{15pt}


\begin{tikzpicture}
\tkzTabInit[nocadre,lgt=1.5,espcl=2.5,deltacl=.5]
{$x$ /.7, $f'(x)$ /.7,$f(x)$ /2}
{$-\infty$ , $-x_0$ , $0$ , $x_0$ , $+\infty$}
\tkzTabLine{ ,+,z,-,z,+,z,-, }
\tkzTabVar{-/$-\infty$ ,+/ $f(x_0)$ ,-/$c$, +/$f(x_0)$,-/$-\infty$}
\end{tikzpicture}

\vspace{15pt}

\begin{tikzpicture}
\tkzTabInit[nocadre]
{$x$ /.7, $f'(x)$ /.7,$f(x)$ /2}
{$-\infty$ ,$\frac{-d}{c}$ , $+\infty$}
\tkzTabLine{ ,-,d,-, }
\tkzTabVar{ + / $\frac{a}{c}$ ,-D+ /$-\infty$/ $+\infty$ , - / $\frac{a}{c}$ }%
\end{tikzpicture}

\vspace{15pt}

\begin{tikzpicture}
\tkzTabInit[nocadre]
{$x$ /.7, $f'(x)$ /.7,$f(x)$ /2}
{$-\infty$ ,$\frac{-d}{c}$ , $+\infty$}
\tkzTabLine{ ,+,d,+, }
\tkzTabVar{ - / $\frac{a}{c}$ ,+D- /$+\infty$/ $-\infty$ , + / $\frac{a}{c}$ }%
\end{tikzpicture}

\end{document}