1/（x+2）-（x^2+2x+1）/（x-2）÷（x^2-1）/（x-1）=1/（x+2）-（x+1）²/（x-2）÷（x-1）(x+1)/（x-1）=1/(x+2)-(x+1)/(x-2)=(x-2-x²-3x-2)/(x+2)(x-2)=[-(x+1)²-3]/(x+2)(x-2)=[-(根号2-1)²-3]/(2-4根号2)=(-1+5根号2)/7
慢慢想想
