\documentclass[11pt]{book}
\usepackage{tikz,pgf}
\usepackage{subfig}
\usepackage{graphicx, array, amsmath}
\usetikzlibrary{shapes, arrows, arrows.meta}
\usepackage{xepersian}
\settextfont{Yas}


\begin{document}

\begin{figure}[h!]
\centering
\begin{tikzpicture}[scale=.6]
\draw[\myc, ->] (-7,0) — (7,0) node[right] {$x_1$};
\draw[\myc, ->] (0,-5) — (0,7) node[above] {$x_2$};
\draw plot[domain=-3:7, samples=10, smooth] (\x, {3-.75*\x}) node[above] {(1)};
\draw[->] (5,-.75) — +(-.3,-.4) [above] node {};
\draw plot[domain=-3:7, samples=10, smooth] (\x, {-2+.5*\x}) node[above] {(2)};
\draw[->] (5,.5) — +(-.3,.6) [above] node {};
\draw (2,-2) to (2,5) node[above] {(3)};
\draw[->] (2,4) — +(-.5,0) [above] node {};
\draw plot[domain=-6:5, samples=10, smooth] (\x, {2+.5*\x}) node[above] {(4)};
\draw[->] (3,3.5) — +(.2,-.4) [above] node {};
\draw (6, -.05) node [below] {(5)};
\draw[->,\myc] (5.5,0) — +(0,.5) [above] node {};
\draw (-.5, 6) node [below] {(5)};
\draw[->,\myc] (0,5.5) — +(.5,0) [above] node {};
\draw[\myc, dashed] plot[domain=-3:3, samples=10, smooth] (\x, {-1.33*\x}) node[above] {$Z=0$};
\draw[\myc, dashed] plot[domain=-2:6, samples=10, smooth] (\x, {4.16-1.33*\x}) node[above] {$Z=12.5$};
\draw[\myc, dashed] plot[domain=-2.5:4.5, samples=10, smooth] (\x, {2-1.33*\x}) node[above] {$\ $};
\draw [pattern color=\mycc, pattern=north west lines] (0,0) to (0,2) to (.8, 2.4) to (2,1.5) to (2,0) to (0,0);
\draw[\myc] (-.1,-.5) node[left] {0};
\draw[\myc] (0,2) node[left] {A};
\draw[\myc] (.8,2.4) node[above] {B};
\draw[\myc] (2,1.5) node[right] {$C^*$};
\draw[\myc] (2,0) node[right] {$D$};
\draw[->,\myc, thick ](0,0) to (1,.75) node[right]{$\overrightarrow{C}$};
%\draw[color=blue] plot[domain=-6.5:6.5] (\x, { 1}) node[right] {};
%\draw[blue] (1,-4.5) — (1,6.5) node[above] {};
%\draw[blue] (-1,-4.5) — (-1,6.5) node[above] {};
\end{tikzpicture}
\caption{}\label{fikh3.1}
\end{figure}

\end{document}