Question

If the 3rd and the 9th terms of an AP are 4 and -8 respectively which term of this AP zero??​

Answer 1

Question :

★ If the 3rd and the 9th terms of an AP are 4 and -8 respectively which term of this AP zero?

Answer :

• Given -

# 3rd term = 4

# 9th term =-8

•To Find -

# Which term is equal to zero .

•Solution -

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

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

(ii) - (i)

6d = -8-4

6d = -12

d = -2

Now, put the value of d in eq(i)

a +2(-2) =4

a -4 = 4

a = 8

Now, We've got the value of both a and d

Now,

An=a + (n-1)d

$0 = 8 + (n - 1) (- 2)$

$0 = 8 - 2n + 2$

$2n = 10$

$n = 5$

The 5th Term of this AP is Zero

Answer 2

Answer:

Question :

★ If the 3rd and the 9th terms of an AP are 4 and -8 respectively which term of this AP zero?

Answer :

• Given -

# 3rd term = 4

# 9th term =-8

•To Find -

# Which term is equal to zero .

•Solution -

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

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

(ii) - (i)

6d = -8-4

6d = -12

d = -2

Now, put the value of d in eq(i)

a +2(-2) =4

a -4 = 4

a = 8

Now, We've got the value of both a and d

Now,

An=a + (n-1)d

0 = 8 + (n - 1) (- 2)0=8+(n−1)(−2)

0 = 8 - 2n + 20=8−2n+2

2n = 102n=10

n = 5n=5

The 5th Term of this AP is Zero

hope it helps .