Find the 17th term?

let the first term of the A.P. is a and the common diff is d

so

6th term=a+5d

9th term=a+8d

acc to qn,

6[a+5d]=9[a+8d]

3a+42d=0

a+14d=0

so 15th term is equal to zero.

we can find the 17th term when we have  values of a and d

but pl check the question, it must be asking to find the 15th term.