Answer
$\textbf{r} = \langle 0,0,0\rangle + t\langle-2,8,-4 \rangle$ = $t\langle-2,8,-4 \rangle$
Work Step by Step
Equation of a Line: $\textbf{r} = \textbf{r}_0 + t\textbf{v}$
$\textbf{r}_0 = \langle 0,0,0\rangle$
We can rewrite $\textbf{r}(t) = \langle 3-2t, 5+8t,7-4t\rangle$ to $\textbf{r}(t) = \langle 3,5,7\rangle + t\langle -2,8,-4\rangle$
We simply have to take the $\textbf{v}$ component of the given $\textbf{r}(t)$ to obtain a parallel line since the $\textbf{v}$ gives the direction of the line.
$\textbf{v} = \langle -2,8,-4\rangle$
$\textbf{r} = \langle 0,0,0\rangle + t\langle-2,8,-4 \rangle$