Proving with Congruence of intergers


by doggie_Walkes
Tags: congruence, intergers, proving
doggie_Walkes
doggie_Walkes is offline
#1
Nov21-09, 12:17 PM
P: 20
It just how do i prove that

b^3 +b^2 +1 does not divide by 5


Im thinking this way,
cause i know that b^3 +b^2 +1 is not congruent to 0(mod5)

therefore we use contradition to prove it. im just not sure how to use contradition? or maybe im looking at this in a completely bad light? maybe there is another method?
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robert Ihnot
robert Ihnot is offline
#2
Nov21-09, 12:31 PM
PF Gold
P: 1,059
This can be worked out by considering all the cases from 0 to 4 mod 5.
Mark44
Mark44 is online now
#3
Nov21-09, 12:54 PM
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P: 20,980
Double posted.


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