Question

The sum of the first 2 terms of a geometric sequence is 8 and the 3rd term of sequence is 18. Find the 1st term of the sequence.

Answer 1

@ganeshie8 @RadEn @hartnn

Answer 2

a+b=8
c=18
b/a=c/b
use b=8-a
(8-a)/a=18/(8-a)
solve this and get a = 2 or 32 its easy to see 32 wont work
so a = 2
and thus b = 6

Answer 3

1st term = 2

Answer 4

why 32 is not the answer...

Answer 5

because the third term is 18, so that would mean you have negative terms, but the 3rd term is positive, and this is geometric

Answer 6

geometric sequence can have negative ratio..

Answer 7

well ok maybe it can be both?
that would make the second term -24
and -24/32 = -3/4
18/-24 = -3/4

Answer 8

ok so both will work....

Answer 9

then 2 and 32 are the answers?

Answer 10

thx

Answer 11

yeah, sort of odd that it asked for one answer