#### Answer

$\textbf{r} = t\langle1,2,3 \rangle$

#### Work Step by Step

Equation of a Line: $\textbf{r} = \textbf{r}_0 + t\textbf{v}$
Given points $(0,0,0)$ and $(1,2,3)$
Use one of the points as $\textbf{r}_0$
$\textbf{r}_0 = \langle 0,0,0\rangle$
Given the two points, we can find $\textbf{v}$:
$\textbf{v} = \langle1-0, 2-0, 3-0\rangle = \langle 1, 2, 3\rangle$
$\textbf{r} = \langle 0,0,0\rangle + t\langle1,2,3 \rangle = t\langle1,2,3 \rangle$