Question

Which term of the A.P. 21 ,18,15,…..is zero? by formula​

Answer 1

Answer:

Robert Hooke FRS was an English scientist and architect, a polymath, recently called "England's Leonardo", who, using a microscope, was the first to visualize a microorganism.

Answer 2

$\huge\bold{Answer:-}$

Given :

The ap is 21 , 18 , 15 ....

To Find :

The no . of term which is 0

solution:

Let, the first term of the ap be a

The common difference is d .

so ,

a = 21

d = ( 18 - 21) = - 3

Let, the n term of the Ap is 0

a + ( n - 1 ) d = 0

21 + ( n - 1 ) -3 = 0

( n -1 ) -3 = -21

( n -1 ) = $\dfrac{-21 }{-3}$

n = 7 + 1

n = 8

Therefore , the 8th terms of the ap is 0