Question

Find the sum of the arithmetic sequence: -94, -112, -130,...; S10

A) 1280
B)-1280
C)-130
D) -1750

Answer 1

D) -1750

Explanation:

`{ \boxed{ \bf{sum = (n)/(2)(2a + (n - 1)d) }}}`

n is number of terms, n=10.

a is first term, a=-94

d is common diffrerence, d = -112-(-94) = -18

`{ \sf{sum = (10)/(2) ( - 188 + (10 - 1) * - 18)}} \\ { \sf{sum = - 1750}}`