Which term of the A.P. 84, 80, 76,… is 0 ?

Given A.P is 84, 80, 76,…

Here, a₁ = a = 84, a₂ = 88

Common difference, d = a₂ – a₁ = 80 – 84 = -4

We know, a_n = a + (n – 1)d where a is first term or a₁ and d is common difference

∴ a_n = 84 + (n – 1)-4

⇒ a_n = 84 – 4n + 4

⇒ a_n = 88 – 4n

Now, to find which term of A.P is 0

Put a_n = 0

∴ 88 – 4n = 0

⇒ -4n = -88

⇒ n = 22

Hence, 22^th term of given A.P is 0