[tex]\bf \begin{array}{ccll}
\stackrel{\textit{years since 2000}}{t}&\stackrel{population}{p}\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
2&29400\\
5&36000
\end{array}\\\\
-------------------------------\\\\
\begin{array}{lllll}
&x_1&y_1&x_2&y_2\\
% (a,b)
&({{ 2}}\quad ,&{{ 29400}})\quad
% (c,d)
&({{ 5}}\quad ,&{{ 36000}})
\end{array}[/tex]
[tex]\bf slope = {{ m}}= \cfrac{rise}{run} \implies
\cfrac{{{ y_2}}-{{ y_1}}}{{{ x_2}}-{{ x_1}}}\implies \cfrac{36000-29400}{5-2}\implies \cfrac{6600}{3}
\\\\\\
2200
\\\\\\
% point-slope intercept
\stackrel{\textit{point-slope form}}{y-{{ y_1}}={{ m}}(x-{{ x_1}})}\implies \stackrel{y}{p}-29400=2200(\stackrel{x}{t}-2)
\\\\\\
p-29400=2200t-4400\implies p(t)=2200t+27200[/tex]
how many in 2007? well, 2007 is 7 years after 2000, thus set t = 7,to get p(t).
