Question

If 3x+k,2x+9 and x+3 are three consecutive terms of an AP find k

Answer 1

The Answer is in the Above picture.

Answer 2

If these are in AP then the common difference would be same
So,
(2x+9)-(3x+k)=(x+3)-(2x+9)
2x+9-3x-k=x+3-2x-9
9-x-k= -x-6
9+6=k
15=k