[tex]\bf ~~~~~~~~~~~~\begin{array}{ccll}
\stackrel{x}{year}&\stackrel{y}{lions}\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
1988&48000\\
2001&25000
\end{array}\\\\
-------------------------------\\\\
\begin{array}{ccccccccc}
&&x_1&&y_1&&x_2&&y_2\\
% (a,b)
&&(~{{ 1988}} &,&{{ 48000}}~)
% (c,d)
&&(~{{ 2001}} &,&{{ 25000}}~)
\end{array}[/tex]
[tex]\bf slope= {{ m}}\implies
\cfrac{\stackrel{rise}{{{ y_2}}-{{ y_1}}}}{\stackrel{run}{{{ x_2}}-{{ x_1}}}}\implies \stackrel{\stackrel{average~rate}{of~change}}{\cfrac{25000-48000}{2001-1988}}
\implies -\cfrac{23000}{13}[/tex]
