Question

What is the sum of a 7-term geometric series if the first term is -6, the last term is -24,576, and the common ratio is 4?

Answer 1

ggggggggggggggg

Answer 2

g what

Answer 3

not helpful -___-

Answer 4

well its easy,im 100 percent sure its math

Answer 5

yeahhh & i need help finding the answer :(

Answer 6

hate math lol

Answer 7

gee thanks ...

Answer 8

lol=)

Answer 9

Common ratio of 4 means you multiply each term by
4 to get the next term.

Answer 10

formula for sum of a geo seq is\[\frac{g_1(1-r^n)}{1-r}\]

Answer 11

use the formula for a geometric series. Sum = (first term) * (1 - r^n)/(1 - r). Just plug in the values of the first term, r and n.

Answer 12

@amistre64 can you please use numbers? i'm dyslexic & the letters are con
fusing me :(

Answer 13

I am not so great at this either was just trying to give you some hints cuz thought maybe that would help. You can also try looking this question up on google an they have example of one similar to this, maybe that would better help u understan... sorry chic:(

Answer 14

its okay :(

Answer 15

show me what you think it says ... at least that way i got something i can work with. Im trying not to just blurt out an answer

Answer 16

g1 = -6 . 1-r^n = -16383

Answer 17

1-r = -2

Answer 18

49149 ?

Answer 19

the first part is excellent; the 1-r tho ... 1 - (4) = -3

this gives us:

-6(-16383)/(-3)

Answer 20

oh oops.

Answer 21

google calculator gives me:

-32766

Answer 22

thats what i got on wolfram

Answer 23

i have one more. its: What is the sum of a 22-term arithmetic sequence where the first term is 57 and the last term is -27?

Answer 24

the answer i got is 300. is that right?

Answer 25

(first + last) times half the n

Answer 26

330 is what i think at first glance

Answer 27

57-27 = 30

11*30 = 330

Answer 28

oh i see what i did wrong