Question

which term of AP 21, 18, 15.... is 0?​

Answer 1

Answer:

here the 1st term a=21

common difference d =18-21= -3

let the n th term is 0

so,

a+(n-1).d=0

=> 21+(n-1).(-3)=0

=> -3(n-1)= -21

=> n-1= -21/-3

=> n-1=7

=> n=7+1

=> n=8

so, the 8 th term is 0

Answer 2

8th term is 0 it is the answer