Question

= 9^(k+1) - 1 = 9^k (9) - 1
how to get like this?​

Answer 1

Step-by-step explanation:

Let

k+9=a

2k−1=b

2k+7=c

To be in AP,

a+c=2b

k+9+2k+7=2(2k−1)

⇒ 3k+16=4k−2

⇒ 3k−4k=−2−16

⇒ −k=−18

∴k=18

For k=18, the terms k+9,2k−1,2k+7 are in A.P

I hope it help

Answer 2

Answer:

k=8

Step-by-step explanation:

I hope this is helpfull for u