Question

State
the
the common is differenced for
given A.P 3​

Answer 1

Answer:

your n is not given so it will be any number from 1 to infinite

Answer 2

Answer:

$\red{\bold{\underline{Answer}}}$

a = 21,

d = 18 – 21 = – 3

and

an = – 81, and we have to find n.

As an = a + ( n – 1) d,

we have;

– 81 = 21 + (n – 1)(– 3)

– 81 = 24 – 3n

– 105 = – 3n

So, n = 35

Therefore, the 35th term of the given AP is – 81.

Next, we want to know if there is any n for which an = 0.

If such an n is there, then;

21 + (n – 1) (–3) = 0,

3(n – 1) = 21

n = 8