Respuesta :

We know, S = n/2 [a + l]

Substitute the known values, 
-7980 = 84/2 [a + l ]
a + l = -7980/42

a+l = -190

In short, Your Answer would be: Option B

Hope this helps!

Answer:

Option B. -190

Step-by-step explanation:

Since the sum of 84 number series is -7980.

We have to find the sum of first and last numbers.

Since sum of an arithmetic sequence is represented as

[tex]S=\frac{n}{2}(first+last)[/tex]

S = [tex]-7980=\frac{84}{2}(First+last)=42(first+last)[/tex]

(First + last) = [tex]\frac{-7980}{42}=(-190)[/tex]

So the total of first and last term is (-190).

Option B. -190 is the correct option.

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