Question

Find the sum of the first 9 terms of the sequence. Show all work for full credit.

2, -7, -16, -25, ...

Answer 1

The sequence subtracts 9
2, -7, -16, -25, -34, -43,-52, -61, -70

Now add. -306

Answer 2

There is no rational way to solve this problem. There is not enough information. If the problem statement actually says "arithmetic sequence", then we're in business. Since it doesn't we'll have to make an assumption. The assumption DSS made was that it was an arithmetic sequence.