化簡(x^2-2xy+y^2-1)/(x-y-1)

化簡(x^2-2xy+y^2-1)/(x-y-1)

x^2-2xy+y^2-1
=(x-y)^2-1^2
=(x-y+1)(x-y-1)
所以原式=(x-y+1)(x-y-1)/(x-y-1)=x-y+1