∵f（x）为（0，+∞）的单调函数，f(f(x)+log12x)＝6令f(x)+log12x=t，∴t为定值（单调）∴f（x）=log2x+t 且f（t）=6∴log2t+t=6，∴log2t=6-t∴t=4∴f（x）=4+log2x f（x）=4+log2x是由y=log2x的图象向上平移4个单...