Answer:
second difference
Step-by-step explanation:
The differences of the y-values will differ by a common amount.
Example:
y = x^2 for x = 2, 4, 6, 8
y-values are 4, 16, 36, 64
differences of these are 12, 20, 28
differences of these differences are 8 and 8, a common value.
