速求约分:x-(y-z)^2/(x+y)^2-x^2还有一条 约分:(x^2-y^2)/(x^2-2xy-3y^2) 亲　帮个忙了

速求约分:x-(y-z)^2/(x+y)^2-x^2还有一条 约分:(x^2-y^2)/(x^2-2xy-3y^2) 亲　帮个忙了
速求约分:x-(y-z)^2/(x+y)^2-x^2
还有一条 约分:(x^2-y^2)/(x^2-2xy-3y^2) 亲　帮个忙了

速求约分:x-(y-z)^2/(x+y)^2-x^2还有一条 约分:(x^2-y^2)/(x^2-2xy-3y^2) 亲　帮个忙了
原式=(x^2-y^2)/(x^2-2xy-3y^2)
=(x+y)(x-y)/(x²-2xy+y²-4y²)
=(x+y)(x-y)/[(x-y)²-(2y²)]
=(x+y)(x-y)/[(x-y+2y)(x-y-2y)]
=(x+y)(x-y)/(x+y)(x-3y)
=(x-y)/(x-3y)
亲,x-(y-z)^2/(x+y)^2-x^2这个式子不是很清晰啊,可以用语言叙述一遍吗?