Will give brainliest and five stars if correct answer for both

1)
Last term of our sum is 110, so answers C) and D) (infinite sums) are incorrect.
Now we can calculate first term (for n = 0) in A) and B):

A)

B)

First term is -10 so B) is correct.

2)
We have:
+ 8 - 40 + 200 - 1000 + ... (different signs)

so there will be (answer A) or B) ).

Calculate first term:

A)

B)

Answer B)