Question 1186017: Find the missing terms in each geometric sequence.
1. ___,___,-16,4,-1
2. 625,___,25,___,1
3. 0.3,___,2.7,___,___.
4. -1/3,___,-4/45,___,8/135,___.
It's okay if there's no solution please help.
Found 2 solutions by Edwin McCravy, ikleyn:
Answer by Edwin McCravy(20056)   (Show Source):
You can put this solution on YOUR website!
1. ___,___,-16,4,-1
4 over -16 is -4/16 which reduces the -1/4
-1 over 4 is also -1/4
So the blank left of 16 is something so that if you multiply it by -1/4
you get -16. If it is x then
  
Can you solve that?
If you can, then the first blank is something so that if you multiply it by -1/4
you get what you got for the second blank.
2. 625,___,25,___,1
If the common ratio is r, the  goes in the second blank
625, 625r,25,___,1
So (625r)(r)=25
625r2=25
r2=25/625
r=5/25
r=1/5
So what does 625r equal?
Multiply 25 by r to get what goes in the other blank
3. 0.3,___,2.7,___,___.
That's the same way as 2, except it uses decimals instead of fractions.
4. -1/3,___,-4/45,___,8/135,___.
You can do that one.
Edwin
Answer by ikleyn(52790)  (Show Source):
You can put this solution on YOUR website! .
In part (2), the ratio of the third term to the first term gives you
r^2 =  ,
which gives TWO possible values for the common ratio r =  and r =  .
They have EQUAL RIGHTS and produce TWO possible geometric sequences.
One sequence is 625, 125, 25, 5, 1.
The other sequence is 625, -125, 25, -5, 1.
So, there are two answers and two possible geometric sequences, instead of one,
as proclaimed by @Edwin.
Similar notice goes to part (3).
Regarding part (4), it is not geometric sequence, at all.
So, you ONLY CAN reject it . . .
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