Answer:
D. Quadratic
Step-by-step explanation:
It can be helpful to look at differences between terms when trying to decide what sort of sequence you have.
Here, the first differences are ...
8-6 = 2
14 -8 = 6
24 -14 = 10
38 -24 = 14
These are not constant (not a linear sequence), and they don't have a common ratio (not an exponential sequence).
However, they do have a common difference:
6 -2 = 4
10 -6 = 4
14 -10 = 4
This set of differences can be called "second differences." The fact they are constant means the sequence can be modeled by a second-degree polynomial, a quadratic.
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Additional comment
Ordinarily, you might look at the ratio of terms to see if they have a common ratio, indicating a sequence is exponential. An exponential sequence will have the same common ratio between terms at any level of differences. So, we can look at the ratios of first- or second-differences to determine if a sequence is exponential. Sometimes those numbers are smaller, and easier to deal with.
If the exponential sequence has an added value (is translated vertically), the original terms won't have a common ratio, but the differences will.
