Answer: D. 11655
Step-by-step explanation:
Given sequence : –4, –1, 2, 5, 8, ...
here, the first term = -4
Common difference = [tex]-4-(-1)=3[/tex]
By Arithmetic progression, the sum of n terms will be
[tex]S_{n}=\dfrac{n}{2}(2a+(n-1)d)[/tex]
Then, the sum of first 90 terms will be
[tex]S_{90}=\dfrac{90}{2}(2(-4)+(90-1)(3))=11655[/tex]
