Question

Which sequences are arithmetic? Check all that apply.

1. –5, 5, –5, 5, –5, …
2. 96, 48, 24, 12, 6
3. 18, 5.5, –7, –19.5, –32, …
4. –1, –3, –9, –27, –81, …
5. 16, 32, 48, 64, 80

Answer 1

-5,5,-5,5,-5,5,-5,5,-5

Answer 2

3. 18, 5.5, –7, –19.5, –32, …

and

5. 16, 32, 48, 64, 80

Step-by-step explanation

An arithmetic sequence has a constant difference.

1. –5, 5, –5, 5, –5, … is not an arithmetic sequence because 5--5≠ -5-5

2. 96, 48, 24, 12, 6 is not an arithmetic sequence because 48-96≠ 24-48

3. 18, 5.5, –7, –19.5, –32, … is an arithmetic sequence because there is a constant difference of

`5.5 - 18 = - 12.5`

4. –1, –3, –9, –27, –81, … is not an arithmetic sequence because

`- 3 - - 1 = - 9 - - 3`

5. 16, 32, 48, 64, 80 is also an arithmetic sequence because

`32 - 16 = 48 - 32`