Question

What is the value of the 30th term in the following arithmetic sequence?

12, 6, 0, -6, ...

a. 186
b. -162
c. -186
d. 342

Answer 1

I believe it’s b but I could be wrong

Answer 2

Answer is C. -186

Because to find the nth term you need to see the pattern . It’s going down in -6 so -6n , then you do inverse to the first number , so +6 to 12 =18 . This makes -6n +18 . This is your formula just substitute n for 30 and you will get -162.

-6 x 30 = -180 , -180 + 18+ -162