Question

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

Answer 1

Step-by-step explanation:

If 3rd term of an AP is 4 then

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

and if 9th term of an AP is -8 then

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

On solving (1) and (2) equation we get,

= -6d=12

=or d= -2

=and a=8

Now let nth term of AP will be 0 then we have,

=Tn=a+(n-1) ×d

=0=8+(n-1) ×(-2)

=-8=(n-1) ×(-2)

=(n-1) =4

=n=5

Hence, 5th term of AP will be 0.