Question

please answer this question ​

Answer 1

Let first term is A

Common difference is d

2term =a+d

7term=a+6d

Add both term as question

a+d+a+6d=2a+7d

15term =a+14d

8term =a+7d

According to question

a+17d-1=2(a+7d)

a+17d-1=2a+14d

3d-1=a

Put value of a in above equation

2(3d-1)+7d=13d=2

D=2/13

Put value of din 3d-1=a

3(2/13)-1=a

-7/13=a

AP.is=a,a+d,a+2d,a+3d.........................

-7/13,-7/13+2/13,-7/13+2(2/13).......

-7/13,-5/13,-3/13.........