Line $L_2$ is $( x, y, z ) = (1, 1, -1) + t(1, -2, -1)$
Find the parametric equation of a line $L_4$ which is different from, yet parallel to, the line $L_2$ given above.
Where I am at so far:
All I know is that two lines in three dimensions are parallel if the direction vectors of both lines are scalar multiples of each other. So I know $L_4$'s direction vector is $(1, -2, -1)$. But that's all I got.