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1025867@etusd.org

 
 
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1025867@etusd.org
by shawn luo - Thursday, March 19, 2020, 7:02 PM
 

What is 2121(mod13)212−1(mod13).

does that mean (2^12-1) (mod 13), or 2^12-1(mod 13), because the second one has many answers

 
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Re: 1025867@etusd.org
by Areteem Professor - Friday, March 20, 2020, 10:37 AM
 

Both $(2^{12} -1) \pmod{13}$ and $2^{12} - 1 \pmod{13}$ mean exactly the same thing. The idea is to find an integer from $0, 1, \dots, 12$, say $a$,  so that $2^{12}-1 \equiv a \pmod{13}$.