\documentclass{article}                                                                                        
 \usepackage{amsmath}                                                                                           
 \usepackage{tikz}                                                                                              
 \usepackage{exam}                                                                                              
 \usepackage{setspace}                                                                                          
                                                                                                                
 \begin{document}                                                                                               
                                                                                                                
 This is one of the special cases mentioned earlier. Our general binomial looks like $ (x + a)(y + b) $, but    
 perfect squares are easier and look like $ (x + a)(x + a) $ which can then be simplified to be $ (x + a)^2 $.  
                                                                                                                
 Remember the trick mentioned earlier? This is it:                                                              
 \begin{enumerate}                                                                                              
     \item Take the first term, square it                                                                       
     \item Take the last term, square it                                                                        
     \item Multiply all the terms with each other                                                               
 \end{enumerate}                                                                                                
                                                                                                                
 Thus we have $ (x + a)^2 = x^2 + 2ax + a^2 $. Simple as that.                                                  
                                                                                                                
 Here is the geometric intuition:                                                                               
                                                                                                                
 \begin{center}                                                                                                 
 \begin{tikzpicture}                                                                                            
     \draw (0,0) rectangle (6,6);                                                                               
     \draw (0,0) rectangle (4,2);                                                                               
     \draw (4,2) rectangle (6,6);                                                                               
                                                                                                                
     \node at (2,6) [above] {$x$};                                                                              
     \node at (0,4) [left] {$x$};                                                                               
     \node at (5,6) [above] {$a$};                                                                              
     \node at (0,1) [left] {$a$};                                                                               
                                                                                                                
     \node at (2,4) {$ x^2 $};                                                                                  
     \node at (5,4) {$ax$};                                                                                     
     \node at (5,1) {$a^2$};                                                                                    
     \node at (2,1) {$ax$};                                                                                     
                                                                                                                
 \end{tikzpicture}                                                                                              
 \end{center}                                                                                                   
                                                                                                                
 We take a square of $x$ units and extend it to a square of length $x+a$:                                       
                                                                                                                
 \begin{examplebox}                                                                                             
     \subsection{Examples}                                                                                      
     Let's only do a few examples this time. We'll come back and do more practise after covering                
 \emph{differences of two squares.}                                                                             
     \begin{doublespace}                                                                                        
     \begin{questions}                                                                                          
         \question[]                                                                                            
         \begin{parts}                                                                                          
             \part \((x-5)^2= \)                                                                                
                 \begin{solutionordottedlines}[1cm]                                                             
                 $x^2 - 10x + 25$                                                                               
                 \end{solutionordottedlines}                                                                    
             \part \((x+7)^2=\)                                                                                 
                 \begin{solutionordottedlines}[1cm]                                                             
                 $x^2 + 14x + 49$                                                                               
                 \end{solutionordottedlines}                                                                    
             \part \((3x-1)^2=\)                                                                                
                 \begin{solutionordottedlines}[1cm]                                                             
                 $9x^2 - 6x + 1$                                                                                
                 \end{solutionordottedlines}                                                                    
         \end{parts}                                                                                            
     \end{questions}                                                                                            
     \end{doublespace}                                                                                          
 \end{examplebox}                                                                                               
                                                                                                                
 \end{document}