Congruence<Text-field layout="_pstyle4" style="_pstyle4">Linear Congruences</Text-field>msolve({3*x=6},9);<Text-field layout="_pstyle4" style="_pstyle4">Application: Check digits and the ISBN system</Text-field>modp(139,11);modp(167,11);modp(140,11);<Text-field layout="_pstyle4" style="_pstyle4">Fermat's theorem and Euler's theorem</Text-field>modp(2^320,321);<Text-field layout="_pstyle4" style="_pstyle4">Application: construction of the regular 17-gon</Text-field>seq(modp(3^n,17),n = 0 .. 15);