Question

What are the first four terms of the sequence a1=−9 and an+1=an+n. I really need help with this im struggling

Answer 1

$a_{n+1}=a_n+n$

The formatting was a bit confusing, so please do let me know if this isn't the correct equation for the sequence.

The first term is given, which is

$a_1=-9$

Now, use the equation for the next terms:

$a_{1+1}=a_2=-9+1=-8$

$a_{2+1}=a_3=-8+2=-6$

$a_{3+1}=a_4=-6+3=-3$

Thus, the first 4 terms are -9, -8, -6, and -3. Let me know if you need any clarifications, thanks!