Which sequences are arithmetic? check all that apply.

–5, 5, –5, 5, –5, …
96, 48, 24, 12, 6
18, 5.5, –7, –19.5, –32, …
–1, –3, –9, –27, –81, …
16, 32, 48, 64, 80

3)    18, 5.5, –7, –19.5, –32, …   sequence is in Arithmetic Progression.

5)     16, 32, 48, 64, 80         sequence is in Arithmetic Progression.

Step-by-step explanation:

If, a, b, c ,k, e ... is a given sequence.

Then the above sequence is in AP if b - a   =  c - b = k - c = ...

or, each term has same COMMON DIFFERENCE (d).

Here, take each sequence and check for the value of d.

1) –5, 5, –5, 5, –5, …

Here, 5 - (-5)  = 10,   -5 - 5  = -10

and 10 ≠ -10.  So the sequence is NOT in Arithmetic Progression.

2)96, 48, 24, 12, 6

Here, 48 - 96  = -48,   24 - 48  = -24

and -48 ≠ -24.  So the sequence is NOT in Arithmetic Progression.

3)18, 5.5, –7, –19.5, –32, …

Here, 5.5 - 18 = -12.5    ,  -7 - 5.5 = -12.5  ..

and -12.5 is the common difference.  

So the sequence is in Arithmetic Progression.

4)–1, –3, –9, –27, –81, …

Here, -3-(-1)  =  - 2     -9 - (-3)  = -6

and -2 ≠ -6.  So the sequence is NOT in Arithmetic Progression.

5)16, 32, 48, 64, 80

Here, 32 - 16 = 16    ,  48  - 32= 16  ..

and 16 is the common difference.  

So the sequence is in Arithmetic Progression.

step-by-step explanation:

i think its about 8