Question

Which of the following sets of points is a direct variation?

(0, 0); (2, 4); (5, 15)
(0, 0); (-1, -2); (1, 2)
(3, 6); (-2, 4); (-1, 2)
(0, 5); (1, 6); (2, 7)

Answer 1

I got the second one. Good Luck. Hope it helped.

Answer 2

(0, 0); (-1, -2); (1, 2) and (0, 5); (1, 6); (2, 7).

Explanation:

The set will have a direct variation if each pair is added or subtracted by a common number in each component. You also can see it graphically, if the points form a straight growing line then the set is a direct variation. Then,

In the first set we have

(0,0), (0+2,0+4), (0+2+3, 0+4+11). The behavior is not uniform, then it is not a direct variation.

Second set: (-1, -2); (0,0); (1, 2)

(-1,-2)(-1+1,-2+2), (-1+1+1, -2+2+2). The behavior is uniform and it is increasing, then it is a direct variaton.

Third set:

(-2, 4), (-2+1,4-2), (-2+1+4, 4-2+4). The behavior is not uniform, then it is not a direct variation.

Fourth set:

(0,5), (0+1, 5+1), (0+1+1, 5+1+1). The behavior is uniform and it is increasing, then it is a direct variaton.