[(1/x-2)-1]/(3-x/x^2-4)

问题描述:

[(1/x-2)-1]/(3-x/x^2-4)

[(1/x-2)-1]/(3-x/x^2-4)
=[(1/X-2)-(x-2)/(x-2)]{[(x+2)(x-2)]/(3-x)}
=[(3-x)/(x-2)][(x+2)(x-2)/(3-x)]
=x+2.