SOLUTION: If you were given the third and the twenty-fifth terms of an arithmetic sequence how would you find the first term???????

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Question 204928: If you were given the third and the twenty-fifth terms of an arithmetic sequence how would you find the first term???????
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
If you were given the third and the twenty-fifth terms of an arithmetic sequence how would you find the first term???????
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a3 = a1 + 2d
a25 = a1 + 24d
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Subtract a3 from a25 to get:
22d = a25 - a3
d = (a25-a3)/22
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Substitute that into a3 to solve for a1.
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Cheers,
Stan H.