Question

If the 8th term of an A.P. is zero, then show that 28th term is double the 18th term.

Answer 1

Step-by-step explanation:

hope that this is the right answer

Answer 2

Answer:

Given:

a₈ = 0

To Prove:

a₂₈ = 2a₁₈

Solution:

We know that a term of an AP can be expressed as:

a + (n - 1)d = an ; Where an is the position of the term.

⇒ a₈ = 0

⇒ a + (8 - 1)d = 0

⇒ a + 7d = 0

⇒ a = - 7d

We have to show that;

⇒ a₂₈ = 2a₁₈

⇒ a + 27d = 2[a + 17d]

⇒ -7d + 27d = 2[-7d + 17d]

⇒ 20d = 2[10d]

⇒ 20d = 20d

⇒ LHS = RHS

Hence, proved.

Step-by-step explanation: