Question

Which sequence is an arithmetic sequence?

A{1,4,16,48,…}

B{−10,−3.5,3,9.5,…}

C{−10,5,−2.5,1.25,…}

D{100,20,4,0.8,…}

Answer 1

The answer is choice B

This is because each time we add on 6.5 to get the next term. For example

term1 = -10

term2 = term1+6.5 = -10+6.5 = -3.5

Another way to see this is to pick any term and subtract off its prior term to get the common difference d

d = (term2) - (term1) = -3.5 - (-10) = -3.5 + 10 = 6.5

Answer 2

Answer:

B

Step-by-step explanation:

This is the only one with the same amount between them. -10 + 6.5 = -3.5.

-3.5 + 6.5 = 3 etc.