Find the sum of the first 12 terms of the sequence. show all work for full credit. 1,-4,-9,-14, ...

Let's find the rule where.

1 - (-4) = 5

-4 - (-9) = 5

It looks like we are subtracting 5 from the previous number. Since we know the rule, let's write out all.

1, - 4, - 9, - 14, - 19, - 24, - 29, - 34, - 39, - 44, - 49, - 54; let's add them.

-318 is the sum