Answer:
A The sum of the first 11 terms is 88
Step-by-step explanation:
Since -4 - (-7) = -1 - (-4) = 2 - (-1) = 3
Your sequence is an arithmetic sequence with a common difference of 3.
The formula for the sum of an arithmetic sequence is
where
In your case , n = 11 and
We know everything except the eleventh term.
So, we need to find the eleventh term or =
+ (n - 1)d
= -7 + (11 - 1)3
= -7 + 30 = 23
Now, S =
The sum of the first 11 terms is 88