数学分式的化简

(x-y)^2-z^2 x^2+xy-xz x^2-(y-z)^2
____________×____________÷____________
2xy+x^2+y^2 x^2-xy x^2-y^2
有点错位。。。

原式
={[(x-y)^2-z^2]*(x^2+xy-xz)*(x^2-y^2)}/{(2xy+x^2+y^2)*(x^2-xy)*[x^2-(y-z)^2]
=[(x-y+z)(x-y-z)*x(x+y-z)*(x+y)(x-y)]/[(x+y)^2*x(x-y)*(x+y-z)(x-y+z)]
=(x-y-z)/(x+y)

（x-y)^2-z^2 x^2+xy-xz x^2-(y-z)^2
解：原式=____________×____________÷____________
2xy+x^2+y^2 x^2-xy x^2-y^2

（x-y+z）(x-y-z) x(x+y-z) (x+y-z)(x-y+z)
= ____________ ×____________÷____________
(x+y)^2 x(x-y) (x+y)(x-y)

（x-y+z）(x-y-z) x(x+y-z) (x+y)(x-y)
= ____________ ×_____________× ___________
(x+y)^2 x(x-y) (x+y-z)(x-y+z)

x-y-z
= ____________
x+y

(x-y-z)/(x+y)

过程如图