SOLUTION: A1= 7, An= -20, Sn = -65 determine n and d.

SOLUTION: A1= 7, An= -20, Sn = -65 determine n and d.

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Question 754618: A1= 7, An= -20, Sn = -65 determine n and d.
Answer by tommyt3rd(5050) (Show Source): You can put this solution on YOUR website!

so that

Therefore

n=10

As for the common difference

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