Question

Determine whether each sequence is arithmetic. If so, identify the common difference.

-3, -1, 1, 3, …
2, 6, 18, 54, …
1, 3, 7, 15, …
32, 25, 18, 11, ...

Answer 1

1 and 4 are airthmeric

Answer 2

Options 1 and 4 are arithmetic

Explanation:

Arithmetic means that you are adding or subtracting a number in a sequence.

For option 1, we are adding 2 every time.

-3 + 2 = -1 -1 + 2 = 1 1 + 2 = 3

For option 4, we are subtracting 7 every time.

32 - 7 = 25 25 - 7 = 18 18 - 7 = 11

Option 2 is geometric. Geometric means you are multiplying or dividing by a number in a sequence.

2 * 3 = 6 6 * 3 = 18 18 * 3 = 54

Option 3 is actually quadratic. This is similar to a arithmetic, except instead, the amount added to the number is multiplied by 2 every time.

1 + 2 = 3 (2 + 2 = 4) 3 + 4 = 7 (4 + 4 = 8) 7 + 8 = 15