Using the distance formula, show that the given points are collinear. (i) (1, -1), (5, 2) and

Using the distance formula, show that the given points are collinear. (i) (1, -1), (5, 2) and (9, 5) (ii) (6, 9), (0, 1) and (-6, -7) (iii) (-1, -1), (2, 3) and (8, 11) (iv) (-2, 5), (0, 1) and (2, -3).