Respuesta :

Answer:

n^2 + 3.

Step-by-step explanation:

4 7 12 19

Differences are 3 5 7   so this a quadratic sequence.

2nd difference = 2 2

So the first part of the expression is n^2

Terms:  4  7  12  19

n^2       1    4   9  16

Difference = 3 3 3 3 3

So the answer is n^2 + 3.

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