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If six times of the 3rd term is equal to the eight times of 7th term in an A.P., then what will be the 19th term? - Algebra

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प्रश्न

If six times of the 3rd term is equal to the eight times of 7th term in an A.P., then what will be the 19th term?

योग

उत्तर

Let a be the first term and d be the common difference.

Then, according to the question,

6a3 = 8a7

⇒ 6(a + 2d) = 8(a + 6d)

⇒ 6a + 12d = 8a + 48d

⇒ 6a – 8a = 48d – 12d

⇒ – 2a = 36d

⇒ a = – 18d

Now, a19 = a + 18d = (– 18d) + 18d = 0

Hence, the 19th term of the A.P. is 0.

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