isabelle/valid/mathd_numbertheory_232.thy (16 lines of code) (raw):

(* Authors: Wenda Li *) theory mathd_numbertheory_232 imports Complex_Main "HOL-Computational_Algebra.Computational_Algebra" "HOL-Number_Theory.Number_Theory" begin theorem mathd_numbertheory_232: fixes x y z::nat assumes "x<31" "y<31" "z<31" and "[x *3 = 1] (mod 31)" and "[y * 5 = 1] (mod 31)" and "[z * (x + y) =1] (mod 31)" shows "z = 29" sorry end