Question

2. Show that the points (–2, 3, 5), (1, 2, 3) and (7, 0, –1) are collinear.

Answer 1

Let points (–2, 3, 5), (1, 2, 3), and (7, 0, –1) be denoted by P, Q, and R respectively.
Points P, Q, and R are collinear if they lie on a line.

Here, PQ + QR =√14 + 2√14 = 3√14 = PR
Hence, points P(–2, 3, 5), Q(1, 2, 3), and R(7, 0, –1) are collinear.