Answer:
93
Step-by-step explanation:
First differences increase by 4 each time. The given numbers are a quadratic sequence that can be described by 2n² -2n +9. The 7th term would be 93.
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First differences are ...
13-9 = 4, 21-13 = 8, 33-21 = 12, 49-33 = 16, 69-49 = 20
Second differences are ...
8-4 = 4, 12-8 = 4, 16-12 = 4, 20-16 = 4
When second differences are constant, the sequence can be represented by a second-degree polynomial function. The leading coefficient is half the value of the second differences.
