x²-3x+2＞0.===>(x-1)(x-2)＞0,===>x＜1,或x＞2.∴函数定义域为(-∞,1)∪(2,+∞).构造复合函数：y=㏑u,u=x²-3x+2.(x∈(-∞,1)∪(2,+∞)).易知,内层函数u=x²-3x+2在(-∞,1)上递减,在(2,+∞)上递增,且u...