设a,b,c,l是适合a+b^2l-1=c^2,2|/bc,c≡-1(mod b^2l)的正整数.运用初等数论方法讨论了方程a^x+b^y=c^z的正整数解(x,y,z),证明了当b≡5或11(mod 24)时,该方程仅有正整数解(x,y,z)=(1,2l-1,2).
Let a,b,c,l be positive integers satisfying a+b^2l-1=c^2,2|/ bc and c≡-1(mod b^2l).In this paper,using some elementary number theory methods,the positive integer solutions(x,y,z)of the equation a^x+b^y=c^z are discussed.It is proved that if b≡5or 11(mod 24),then the equation has only the positive integer solution(x,y,z)=(1,2l-1,2).