解： 【[1/(x+2)]-1】÷[(x^2+2x+1)/(x^2-4)]， =[1-(x+2)]/(x+2)÷{(x+1)²/[(x+2)(x-2)]}=-(x+1)/(x+2)·[(x+2)(x-2)]/(x+1)²=-1/[(x-2)(x+1)]把x=-2代入上式=-1/[(-2-2)×(-2+1)]=-1/4
