Question

In which choice do all three points lie on the

same straight line?
A А.
(0, 1), (-1, 3), (1, 3)
B.
(4, 2), (2, 1), (4, -2)
C (0, 0), (8, 0), (0, 8)
D
(1, 2), (2, 4), (4,8)

Answer 1

D (1, 2), (2, 4), (4,8)

Explanation:

Points lying on the same line:

If three points lie on the same line, the change in y has to be always the same when x changes by 1.

А. (0, 1), (-1, 3), (1, 3)

(-1,3) to (0,1): x changes by 1, y by -2

(0,1) to (1,3): x changes by 1, y by 2

So these points are not on the same line.

B. (4, 2), (2, 1), (4, -2)

Two values for y when x = 4, so not on the same straight line.

C (0, 0), (8, 0), (0, 8)

Two values for y when x = 0, so not on the same straight line.

D (1, 2), (2, 4), (4,8)

Here, when x changed by 1(from 1 to 2), y changed by 2.

When x changed by 2(from 2 to 4), y changed by 2*2 = 4.

So these points are on a straight line, and D is the correct answer.