No Integral Solution for x & y when c Not Divisible by d

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Homework Help Overview

The discussion revolves around the conditions under which the linear equation ax + by = c has integral solutions for integers x and y, particularly focusing on the implications of divisibility by an integer d.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the implications of the divisibility of a and b by d, questioning the introduction of d into the equation. There is an attempt to reformulate the equation by substituting a and b with their expressions in terms of d.

Discussion Status

The discussion is ongoing, with participants questioning the validity of certain steps taken in the manipulation of the equation. There is no explicit consensus on the correctness of the approach or the conclusion regarding the existence of integral solutions.

Contextual Notes

Participants are examining the implications of c not being divisible by d, which is central to the problem's conditions. There is uncertainty regarding the manipulation of the equation and the assumptions made about the divisibility of the variables involved.

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Homework Statement


For, a, b, c[tex]\in[/tex]integers and D[tex]\in[/tex]integers -{0}, if a and b are divisible by d, and c is not divisible by d then the equation ax+by=c has no integral solution for x and y.


Homework Equations





The Attempt at a Solution


ax+by=c
a/dx+b/dx=c
1/d[ax+by]=c
ax+by=cd
 
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Where did the d in a/d come from? You can't just "stick" it into part of the equation.

Saying "d divides a" means a= dn for some integer n. Saying "d divides b" means b= dm for some integer m. Replace a and b in your equation by that and see what happens.
 
HallsofIvy said:
Where did the d in a/d come from? You can't just "stick" it into part of the equation.

Saying "d divides a" means a= dn for some integer n. Saying "d divides b" means b= dm for some integer m. Replace a and b in your equation by that and see what happens.

dnx+dmx=c
d(nx+mx)=c
 
I don't know if that was the correct way to do it and then maybe say since we don't have a dpc then there is no integral solution?
 

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