# Solving a Linear Diophantine Equation in Two Variables by the Euclidean Algorithm

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This Demonstration shows the solutions of Diophantine equations of the form , and using the Euclidean algorithm.

Contributed by: Izidor Hafner (September 2016)

Open content licensed under CC BY-NC-SA

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A linear Diophantine equation can have either no solutions, exactly one solution or infinitely many solutions.

Let and be nonzero integers, and let . The equation always has a solution in integers, and this solution can be found by the Euclidean algorithm. Then every solution to the equation can be obtained by substituting for the integer in the formula

[1, p. 37].

If , then we have the equation , which is . It has one solution , and the general solution is .

The homogeneous equation has the general solution .

The Diophantine equation has no solution if if not divisible by . If , then the equation has the general solution , so that .

[1]. J. H. Silverman, *A Friendly Introduction to Number Theory*, Upper Saddle River, NJ: Prentice Hall, 1997.

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