Question

if the 3rd and the 9th terms of an AP are 4 and -8 respectively , which term of the AP is zero.please give step by step​

Answer 1

Answer:

5th term

Step-by-step explanation:

Given

a3 = 4

a9 = -8

WKT,

a = (n-1)d

So, we can write,

a3 = a + 2d

a +2d = 4.............(1)

a9 = a+ 8d

a + 8d = -8............(2)

Subtracting (1) from (2) , we get

d = -2

Substituting d = -2 in (1) , we get

a = 8

WKT,

an = a + (n-1) d

0 = 8 + (n-1) -2

-8=(n-1)-2

4=n-1

n=5

Therefore, 0 is the 5th term of the given AP.