Question

in an A.P nine times ninth term is equal to fifteen times fifteenth term show that six times twenty fourth term is equal to zero​

Answer 1

here is the answer...........

let the first term be a

and common difference be d

so, 9th term = a + 8d

15th term = a + 14d

Now, according to question:-

9( a + 8d) = 15( a + 14d)

after solving it we will get....

a = -23d.......(i)

Now,

To show:-

6(a+ 23d) = 0........(ii)

put (i) in (ii)

6(-23d + 23d)

6(0)

0

Hence shown.......