令a=16,b=4f(a/b)=f(a)-f(b)f(4)=f(16)-f(4)f(16)=2f(4)=2所以f(x+6)-f(1/x) > f(16)令a=x+6,b= 1/xf(x+6)-f(1/x)=f(a/b)=f(x²+6x)f(x²+6x) > f(16)因为f(x)是定义在(0,∞)的减函数所以x²+6x < 16x+6...