Area of triangle having angular points (x1,y1) (x2,y2) (x3,y3) is given by the formula
△=12|x1y2+x2y3+x3y1−x2y1−x3y2−x1y3|
△=12|1×(−2)+3×16+(−3)×4−3×4−(−3)(−2)−1×16|
⇒△=0
⇒ All three points are in a straight line.