x2-4分之2x-x-2分之1
问题描述：
x2-4分之2x-x-2分之1
答
=2x/(x+2)(x-2)-(x+2)/(x+2)(x-2)
=[2x-(x+2)]/(x+2)(x-2)
=(2-x)/(x+2)(x-2)
=-1/(x+2)