Could this set if ordered pairs have been generated by a linear 20)
a. no, because the distance between consecutive y-values is different than the distance between consecutive x-values.
b. yes, because the relative difference between y-value and x-value is the same no matter which pairs of (x, y) you use to calculate it
c. yes, because the distance between consecutive x-value is constant
d. no, because the y-value decrease and then increase