[tex]\bf \begin{array}{lllll}
&x_1&y_1&x_2&y_2\\
% (a,b)
&({{ 2003}}\quad ,&{{ 510000}})\quad
% (c,d)
&({{ 2012}}\quad ,&{{ 810000}})
\end{array}
\\\\\\
% slope = m
slope = {{ m}}= \cfrac{rise}{run} \implies
\cfrac{{{ y_2}}-{{ y_1}}}{{{ x_2}}-{{ x_1}}}\implies\cfrac{810000-510000}{2012-2003}\leftarrow
\begin{array}{llll}
average\\
rate\ of\\
change
\end{array}[/tex]
