Question

if A1 A2 A3 are an in AP such that a4 - a7-a10=m and the 9th term is n. then find the 8th term of the sequence.
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Answer 1

Answer:

13m.

Step-by-step explanation:

Let d be the common difference of the given A.P.

Given in the A.P., a4 - a7 + a10 = m

⇒a1 + 3d - (a1 + 6d) + a1 + 9d = m

⇒a1 + 6d = m...(1)

Now the sum of first 13 terms of the A.P. is

$\frac{13}{2}$ (2a1 + 12d)

= 13 (a1 + 6d)

= 13m.

- $Shahrin$ $Khan$