1、a/ab+a+1 =a/ab+a+abc = 1/b+1+bc所以,a/ab+a+1+ b/bc+b+1 =1+b/bc+b+1= abc+b/bc+b+abc = ac+1/c+1+ac所以,原式= ac+1/c+1+ac +c/ca+c+1 =12、原式=a/b + a/c + b/c+ b/a +c/a + c/b +3 =a+c/b ...