#### Answer

$\textbf{r} = \langle 2,4,8\rangle + t\langle5,1,-5 \rangle$

#### Work Step by Step

Equation of a Line: $\textbf{r} = \textbf{r}_0 + t\textbf{v}$
Given points $(2,4,8)$ and $(7,5,3)$
Use one of the points as $\textbf{r}_0$
$\textbf{r}_0 = \langle 2,4,8\rangle$
Given the two points, we can find $\textbf{v}$:
$\textbf{v} = \langle7-2, 5-4, 3-8\rangle = \langle 5,1,-5\rangle$
$\textbf{r} = \langle 2,4,8\rangle + t\langle5,1,-5 \rangle$