Question

ARITHMETIC PROGRESSIONS
0.12. For what value of k will k + 9,2-1 and 2x + 7 are the consecutive terms of an Ap? plz explain​

Answer 1

Answer:

Given, k+9,2k-1 and 2k+7

Let us take k=1,

10,1,9 Therefore for k=1 is not an arithmetic progression.

Let us take k=2,

2,11,3,11 for k=2 is not an arithmetic progression.

for k=3,

12,5,13 for k=3 is not an arithmetic progression.

for k=4, and so on up to the 18.

for k=18,

27,35,43 here d=8

(OR)

Given numbers, k+9,2k-1,2k+7

t1=k+9,t2=2k-1, t3=2k+7

In A.P. difference is same. d=t2-t1=t3-t2

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

==>k-10=8

Therefore k=18.