What is the sum of the geometric sequence -4,24,-144...if there are 8 term? A.-959,781 B. 29,637 C. 26,661 D. 959,780 PLEASE HELP

Respuesta :

it is d because I know it guys trust me it is easy.

Answer:

The sum of 8 terms of series is 959,780

D is correct

Step-by-step explanation:

Given: -4, 24, -144, ......

There are 8 terms.

We need to find the sum of 8 terms.

First term, a=-4

Common ratio, r=-6

[tex]a_n=-4\cdot(-6)^{n-1}[/tex]

Sum of 8 term

[tex]Sum=a_1+a_2+a_3+a_4+a_5+a_6+a_7+a_8[/tex]

[tex]Sum=\sum_{n=1}^{8}a_n[/tex]

[tex]Sum=-4+24-144+864-5184+31104-186624+1119744[/tex]

[tex]Sum=959,780[/tex]

Hence, The sum of 8 terms of series is 959,780