Question

The difference between 5th and 9th term of an arithmetic sequence is 20 . What is the difference between the 3rd and the 1st term ?​

Answer 1

Answer:

Answer: A5 =26. Step-by-step explanation: An =5n+1.02-Oct-2020

Step-by-step explanation:

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Answer 2

Answer:

Let first term =a

Common difference =f

Then 5th term =a+4d=20…………….(i)

8th term =a+7d=110………………………(ii)

Subtract (i) from (ii) and get

3d=90 Hence d=90/3=30

And a=20–3d=20–4×30=-100

Sum of first three terms-=-100+(-100+30)+(-100+60)=-100–70–40=-210

Step-by-step explanation:

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