Question

Here are the first five terms of a quadratic sequence. 9 24 47 78 117 Find an expression, in terms of n, for the nth term of this sequence.
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Answer 1

Answer:

4n^2+3n+2

Step-by-step explanation:

9 24 47 78 117

 15  23

     8

8/2 = 4

=4n^2

9-4 = 5 (the minus value come from 4n^2 where n is the position where 9 lays)

24-16 = 8

47-36 = 11

so plus 3 every time so 3n

4n^2+3n for the first value is 7 so you need an extra 2

4n^2+3n+2