Show that there does not exist x,y,z

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SUMMARY

This discussion focuses on proving the non-existence of integer solutions (x, y, z) for the system of equations defined modulo 7. The equations are: 2x + 4y ≡ 1 (mod 7), x + y + 4z ≡ 2 (mod 7), and y + 3z ≡ 3 (mod 7). Participants suggest using linear algebra techniques in the finite field F7, emphasizing that traditional methods such as substitution or elimination may not be effective. The key insight is to combine the second and third equations to simplify the problem.

PREREQUISITES
  • Understanding of modular arithmetic, specifically modulo 7.
  • Familiarity with linear algebra concepts applicable in finite fields.
  • Knowledge of solving systems of equations using substitution and elimination methods.
  • Basic proficiency in working with integers and their properties in modular systems.
NEXT STEPS
  • Study the properties of finite fields, particularly F7.
  • Learn how to apply linear algebra techniques to solve equations in modular arithmetic.
  • Explore the implications of integer solutions in modular systems.
  • Practice solving similar systems of equations to reinforce understanding of the concepts discussed.
USEFUL FOR

This discussion is beneficial for mathematics students, particularly those studying abstract algebra, number theory, or anyone interested in solving modular arithmetic problems.

rooski
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Homework Statement



Show that there does not exist integers x,y,z such that

2x + 4y === 1 (mod 7)
x + y + 4z === 2 (mod 7)
y + 3z === 3 (mod 7)


The Attempt at a Solution



Should i be using substitution or elimination to solve this?

I could do something like

2x + 4y + 0z
x + y + 4z
_________
x + 3y - 4z


Or am i going in the wrong direction?
 
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hi rooski! :smile:

hint: try adding the second and third equations :wink:
 
Another suggestion, work in the field F7 (in fact you do but, someway not really -> anyway, forget about the mod 7 and keep in mind it is F7 which behaves like R)

After that you can just do linear algebra (you probably already learned for R and C) to finish your question
 

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