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- Feb 5th 2007, 07:51 AM #1

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## GCD=1 Problem

Let r,s,t be integers. If r=st+1, prove gcd(r,s) = 1.

My works so far:

I know that to prove gcd(r,s) =1, I need to have ra + sb = 1 for some integers a and b.

Now r = st + 1 means 1 = r - st.

Well, r = r(1) and - st means + s(-b)

So 1 = r(1) + s (-t)

Is that right?

Thank you.

KK

- Feb 5th 2007, 08:02 AM #2

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- Feb 5th 2007, 08:04 AM #3

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