Question

What is the sum of an 8-term geometric series if the first term is -11, the last term 180,224, and the common ratio is -4? answers to choose from. can somebody please solve this?

a)-143,231
b)-36,047
c)144,177
d)716,144

Answer 1

@Mr.Me

Answer 2

@hba

Answer 3

@CalebBeavers

Answer 4

@baldymcgee6

Answer 5

@heyheuhru

Answer 6

@yashar806

Answer 7

@saud_s2k

Answer 8

@DLiberal

Answer 9

@Algebraic!

Answer 10

Somebody please help

Answer 11

@gordonke

Answer 12

@quietstorm93

Answer 13

just use the formula

Answer 14

I am not good at this stuff

Answer 15

http://www.lastminutemaths.com/Flashcard_files/Geometric_series.jpg

Answer 16

Ive tried working it out and i believe the answer is 144,177 is this right?

Answer 17

@baldymcgee6

Answer 18

@heyheuhru could you please tell me if im correct please.

Answer 19

@algebraic could you please help me

Answer 20

@surdawi could you please help me?

Answer 21

Hiiii @surdawi i believe the answer to this problem is 144,177

Answer 22

Would you like me to xplain how to answer it my friend?

Answer 23

Yes that would be great but at the end could explain if my answer is correct?

Answer 24

We can do both..I will go through the problem step by step for you
i am alittle laggy so bear with me though

Answer 25

Okay sounds good lol

Answer 26

Basically you use the negative 4 to go from -11 to 180224
so -11 x -4 = 44
44 x -4 =-176 and so on ..so the answers or terms are -11, 44, -176, 704, -2816, 11264, -45056, and 180224. Now those are your terms for the sum..just add them all together ..I did it as such -11 + 44 - 176 + 704 - 2816 .... to reduce on symbols. And i got C .

Answer 27

Awesome i got the same answer was just very unsure i have about 15 more problems if ineed your help could you help i need to have them done before midnight its a lot of makeup work? @Spectrum

Answer 28

All of the problems are like this @Spectrum

Answer 29

And ill give medals for every one answered please??

Answer 30

@Spectrum ?

Answer 31

well ill try to be of service..i might have to unplug computer and reconnet somewhere else in a bit though k?

Answer 32

That's fine i just really need this to be done and your the only real help i have gotten and ive been on openstudy all day so i would greatly appreciate this

Answer 33

alright then