What is the common difference in the sequence 9, 4, -1, -6?

a. 5

b. -5

c. 9

d. -11

(am i dividing or subtracting? )

Use first differences. You are subtracting. Difference = Subtracting.

9 - x = 4
4 - x = -1
-1 - x = -6

Find for x.

9 - x = 4
   - x = 5
     x = -5

Therefore the answer is B.

Proof:

9 - 5 = 4
4 - 5 = -1
-1 - 5 = -6
    

It’s either a or c as the answer.

Photo math will give you the step by step answer : )