The question:
The line L1 has equation $$r = \left( \begin{array}{ccc}4 \\-1 \\0\\\end{array} \right) + t\left( \begin{array}{ccc}1 \\1 \\-1\\\end{array} \right) $$, and point A has coordinates (4, 8, -3).
Find the coordinates of point B on L1, such that $$\overrightarrow{AB}$$ is...