Question

if the 3rd and the 9th terms of an A.P. are 4 and - 8
respectively. Which term of this A. P. is zero?​

Answer 1

Answer:

hence the 5th term of AP is zero

Answer 2

Answer:

5th term.

Step-by-step explanation:

a+2d= 4.........(i)

a+8d=-8.........(ii)

Subtract (i) from (ii):-

a+8d-a-2d= -8-4

6d= -12.

d= -2.

Substitute in (i)

a+2(-2)=4.

a= 4+4= 8.

Now, an= 0 and n= ?

Since, an= a+(n-1)d.

0= 8+(n-1)-2

-8= (n-1)-2.

n-1= -8/-2= 4

n= 4+1=5th term.