Direction ratios of the line joining A and B are (1 – 2), (–2 –3), (3 + 4) i.e., –1, –5, 7
Direction ratios of the line joining A and C are (3 – 2), (8 – 3), (–11 + 4) i.e., 1, 5, –7
It is clear that direction ratios of line AB and AC are proportional.
⇒ Parallel vectors of both lines are parallel to each other.
⇒ Both given lines are parallel.
⇒ But point A is common. So, points ABC are collinear.
