Proof for a higher level math class

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SUMMARY

The discussion centers on proving the mathematical statement "ac | bc if and only if a | b." Participants emphasize that while examples can illustrate concepts, they cannot serve as definitive proofs. The proof requires demonstrating that if ac divides bc, then b must also be an integer multiple of a. This involves manipulating the equation bc = k * ac to derive the necessary implications regarding the divisibility of a and b.

PREREQUISITES
  • Understanding of divisibility in integers
  • Familiarity with mathematical proofs and implications
  • Knowledge of integer multiples and their properties
  • Basic algebraic manipulation skills
NEXT STEPS
  • Study the concept of divisibility in number theory
  • Learn about constructing formal mathematical proofs
  • Explore counterexamples and their role in mathematical reasoning
  • Investigate implications and equivalences in mathematical statements
USEFUL FOR

Students in higher-level mathematics, particularly those studying number theory or proof techniques, as well as educators seeking to enhance their teaching of mathematical proofs.

aesailor
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Homework Statement



ac | bc if and only if a | b (Note that this is really two implications.)



2. The attempt at a solution

The only way I can see going about this proof is by using examples. I know that in ac | bc the c will cancel out in both, but I don't know how to properly word the proof. Any suggestions would be greatly helpful.
 
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aesailor said:

Homework Statement



ac | bc if and only if a | b (Note that this is really two implications.)



2. The attempt at a solution

The only way I can see going about this proof is by using examples. I know that in ac | bc the c will cancel out in both, but I don't know how to properly word the proof. Any suggestions would be greatly helpful.
You can use examples to disprove a statement (these are called counterexamples), but you can't use examples to prove a statement.

For the direction ac | bc ==> a | b, since ac divides bc, then bc must be some integer multiple of ac, so bc = k * ac, for some integer k. Can you show that this implies that b must be an integer multiple of a?
 

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