To find the nth term of this sequence, the first step is to find the common difference between each term; the difference between 3 and 12 is 9 and then the difference between 25 and 12 is 13. The second step is to find the second difference which is between 13 and 9 which is 4. We have found the second difference of the sequence which is 4. We have noticed this is a quadratic sequence and the seco... more