Question

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

Answer 1

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