## anonymous one year ago Which sequences are geometric? Check all that apply. –2, –4, –6, –8, –10, … 16, –8, 4, –2, 1 –15, –18, –21.6, –25.92, –31.104, … 4, 10.5, 17, 23.5, 30, … 625, 125, 25, 5, 1, …

1. anonymous

@apalmer004 The last question you asked on the others, Number 2 was not one of them, only the last 2. Sorry.

2. misty1212

weird i swear i just saw this exact question

3. anonymous

Misty will be able to help you here, I gotta go to the movies

4. misty1212

what are you going to see?

5. anonymous

do you know the answer? @misty1212

6. misty1212

see which ones have a "common ratio" i.e if you divide one term by the previous one, you always get the same number

7. misty1212

not $–2, –4, –6, –8, –10, …$ since there you are subtracting 2 each time, so it is "arithmetic"

8. misty1212

$16, –8, 4, –2, 1$ is geometric since $\frac{-8}{16}=\frac{8}{-8}=\frac{-2}{4}=\frac{-1}{-2}$ all the ratios are $$-\frac{1}{2}$$

9. misty1212

typo there, i meant $\frac{-8}{16}=\frac{4}{-8}=\frac{-2}{4}=\frac{-1}{-2}$

10. misty1212

for $–15, –18, –21.6, –25.92, –31.104, …$ check using a calculator if $\frac{-18}{-15}=\frac{-21.6}{-18}=\frac{-25.92}{-21.6}$