Question

the algebraic expression of a sequence is 81-8n.what is sum of first 10 term​

Answer 1

Step-by-step explanation:

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refer to the attachment ✌️

Answer 2

Answer:

For n = 1, a1 = 81 - 8 = 73

For n = 2, a2 = 81 - 8 × 2 = 81 - 16 = 65

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.

For n = 10, a10 = 81 - 8×10 = 1

So first term, a = 73

and a10 = 1

n = 10

So sum of 10 terms =

$\frac{10}{2} (a1 + a10) \\ = 5 \times (73 + 1) \\ = 5 \times 74 \\ = 370$