Answer
$N=5t-20$
Work Step by Step
A linear model has form $N=mt+b,$
t represents years after 2000.
We are given two points on the graph: $(6,10)$ and $(9,25),$
Calculate slope:
$m=\displaystyle \frac{25-10}{9-6}=\frac{15}{3}=5$
So far, $N=5t+b.$
Substituting $(t,N)=(6,10)$, we solve for b
$10=5(6)+b$
$10=30+b\qquad /-30$
Thus,
$N=5t-20$
