Answer
$g(0) = 12,837$
$g(3) =7608.54 $
Work Step by Step
Given
$$g(t) =12837\cdot (0.84)^{t} $$
Set $t= 0$ and $t= 3$ to find $g(t)$
\begin{equation}
\begin{aligned}
g(0)&=12837\cdot (0.84)^{0}\\
&= 12,837\\
g(3)&=12837\cdot (0.84)^{3}\\
&= 7608.54\\
\end{aligned}
\end{equation}