\documentclass[12pt]{article}
\usepackage{amsmath, amssymb, graphicx, array, fancyhdr, unicode-math, multirow}
\DeclareMathOperator{\Var}{Var}
\DeclareMathOperator{\sd}{SD}
\DeclareMathOperator{\Pois}{Pois}
\DeclareMathOperator{\Bin}{Bin}
\DeclareMathOperator{\NegBin}{NegBin}
\DeclareMathOperator{\sech}{sech}
% Text: Calibri, all bold
\setmainfont{Calibri}
\renewcommand{\seriesdefault}{b}

% Math: choose a math font and visually embolden it
\setmathfont{TeX Gyre Termes Math}                  % base math font
\setmathfont[FakeBold=1.9]{TeX Gyre Termes Math}    % embolden; adjust 1.6–2.4

% header
\pagestyle{fancy}
\fancyhf{}
\lhead{\resizebox{!}{2cm}{E}}
\chead{\raisebox{0.5cm}{\Huge Introduction}} % (add title text if you want)
\rhead{\resizebox{!}{2cm}{E}}
\setlength{\headheight}{2.5cm}
\setlength{\headsep}{12pt} % space between header and body

\begin{document}
\thispagestyle{fancy}

\begin{table}[h!]
\centering
\setlength{\fboxsep}{4pt}   % consistent padding
\setlength{\fboxrule}{1pt}  % consistent border
\renewcommand{\arraystretch}{1.2}

\begin{tabular}{>{\centering\arraybackslash}m{1.2in} >{\centering\arraybackslash}m{4in}}
\fbox{\includegraphics[height=1in]{images/single.png}}
&\includegraphics[height=1in]{images/Section_01_E_Small.png} \\
\\
\end{tabular}

\begin{tabular}{>{\centering\arraybackslash}p{1.2in} >{\centering\arraybackslash}p{4in}}
\multirow{2}{*}{\fbox{\includegraphics[height=1in]{images/abstract.png}}}
& $x \in A$ \\
& $x \in B$ \\
& $\therefore A \subseteq B$ \\
\\
\\
\\
\end{tabular}

\begin{tabular}{>{\centering\arraybackslash}m{1.2in} >{\centering\arraybackslash}m{4in}}
\fbox{\includegraphics[height=1in]{images/question.png}}
&\includegraphics[height=1in]{images/Three_sets_subsets.png} \\
&$A \subseteq B, B \subseteq C$\\
&$A \subseteq C \rightarrow ?$\\
\end{tabular}

\end{table}

% second page
\newpage
\thispagestyle{fancy}

\begin{table}[h!]
\centering
\setlength{\fboxsep}{4pt}   % consistent padding
\setlength{\fboxrule}{1pt}  % consistent border
\renewcommand{\arraystretch}{1.2}


\begin{tabular}{>{\centering\arraybackslash}m{1.2in} >{\centering\arraybackslash}m{4in}}
\fbox{\includegraphics[height=1in]{images/key.png}} 
&\includegraphics[height=1in]{images/Three_sets_subsets.png} \\
&$A \subseteq B, B \subseteq C$\\
&$x \in A \rightarrow x \in B (\because A \subseteq B)$\\
&$x \in B \rightarrow x \in C (\because B \subseteq C)$\\
&$\therefore A \subseteq C)$\\
\end{tabular}

\end{table}

\end{document}
