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Number Theory/Congruence question

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Question

Question
Please look at the image attached.
Thanks a lot.

Answer
Hello Tom
To prove that x(s) is in Z, expand by the binomial.  The 1/a terms cancel, and all the rest are integral.
ax_1 = 1 mod m, then 1-ax_1 = km with k integral.
Then (1-ax_1)^s = (km)^s.

Now we calculate ax_s = a(1/a - 1/a(km)^s) = 1 - (km)^s = 1 (mod m^s).
So x_s is the solution required.

Best wishes

vijilant

Vijilant

Expertise

Most questions on number theory, divisibility, primes, Euclidean algorithm, Fermat`s theorem, Wilson`s theorem, factorisation, euclidean algorithm, diophantine equations, Chinese remainder theorem, group theory, congruences, continued fractions.

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Teacher of math for 50 years

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