已知X²-5X-2007=0 则代数式（X-2)²-(X-1)²+1／X-2 的值为
原式=（x-2)²-（x-1)²+1²／x-2
=（x-2)²-（x-1-1）(x-1+1）／x-2
=(x-2)²-(x-2)x／x-2
=x-2(x-2-x）／x-2
=-2