Question

Find k given that 3k + 1, k and -3 are consecutive terms of an arithmetic sequence.

Answer 1

3k +1, k, -3 Three consecutive terms of an arithmetic sequence. Find k.

Did I write the problem correctly?

Answer 2

Yes, you are right.

Answer 3

Let x be the common difference of the sequence.

Then,

3k+1 + x = k and
k + x = -3
------------

2k + x = -1
k + x = -3
------------

Subtract to add out the x terms

k = -1 + 3 = 2

Answer 4

3k +1, k, -3 when 2 is substituted for k becomes:

7, 2, -3

The common difference is 5

7-5 = 2

2 - 5 = -3


So k =2 does work.

Questions: @elifbestegul

Answer 5

Thank you. @directrix

Answer 6

You are welcome.