Question

plzz answer with explanation
I will mark as brainiest.. 100% sure
but it should be right answer​

Answer 1

Assuming
K + 9 , 2k - 1 , 2k + 7 are in A.P
then
2k - 1 - k - 9 = 2k + 7 - 2k + 1
(If a,b,c are in
A.P then b- a = c - b = common difference)
So
K - 10 = 8
K = 18

Answer 2

We know that a2 - a1 = a3 - a2 = d (common difference)

Since k + 9, 2k - 1 and 2k + 7 are in AP

i.e. a1 = k + 9, a2 = 2k -1 and a3 = 2k +7

Putting then in above equation,

2k + 7 -( 2k - 1) = 2k -1 - (k + 9)

2k + 7 - 2k + 1 = 2k -1 - k - 9

8 = k - 10

k = 10 +8

K = 18