Maths 因式分解

-xy(x-y)^2+x(y-x)^2-xy(x-y)^2
-xy(x-y)^2+x(x-y)^2-xy(x-y)^2
(x-y)^2(-xy+x-xy)
(x-y)^2(x-2xy)
x(x-y)(1-2y)

2010-01-30 20:44:49 補充：
個正負唔洗change!!x(y-x)^2

2010-01-30 20:46:40 補充：
(y-x)^2=y^2-2xy+x^2

(x-y)^2=x^2-2xy+y^2
=y^2-2xy+x^2

so 個正負唔洗change!!

2010-01-30 20:48:57 補充：
-xy(x-y)^2+x(y-x)^2-xy(x-y)^2
-xy(x-y)^2+x(x-y)^2-xy(x-y)^2
(x-y)^2(-xy+x-xy)
(x-y)^2(x-2xy)
x(x-y)^2(1-2y)

2010-01-30 20:49:43 補充：
The first answer is wrong!!

2010-01-30 20:50:29 補充：
002的ans is wrong!

2010-01-31 15:46:27 補充：
thenna1020 你呢D叫展開,唔係因式分解.......

2010-02-01 22:58:28 補充：
在二次中係唔洗change!

你see(x-y)^2同(y-x)^2有咩分別?

(x-y)^2
x^2-2xy+y^2

(y-x)^2
y^2-2xy+x^2

2010-02-01 22:59:23 補充：
(y-x)^2
y^2-2xy+x^2
x^2-2xy+y^2

2010-02-01 23:05:24 補充：
-xy(x-y)+x(y-x)-xy(x-y)
-xy(x-y)-x(x-y)-xy(x-y)
(x-y)(-xy-x-xy)
(x-y)(-x-2xy)
-(x-y)(x+2xy)
x(y-x)(1+2y)

如果有(y-x)有二次)(y-x)^2)符號係唔洗change!

但冇二次就一定要change!(y-x)=-(x-y)

2010-02-01 23:06:50 補充：
你去計(y-x)^2同(x-y)^2兩條,你就會明我say 咩!

2010-02-02 19:26:26 補充：
乂冰封記憶,你本身都計到,但係唔小心,下次小心D!!(加油)

p4b31t,恭喜你學到野!

1. -xy(x-y)^2+x(y-x)^2-xy(x-y)^2

=-xy[(x)^2-2(x)(y)+(y)^2]+x[(y)^2-2(y)(x)+(x)^2] -xy[(x)^2-2(x)(y)+(y)^2]

= x[(y)^2-2(y)(x)+(x)^2]

=xy^2-2xy=x^2

根據公式:a^2 -2a b+b^2

2010-01-30 21:59:29 補充：
如有錯誤請指導

2010-01-31 14:55:31 補充：
答案是=xy^2-2xy+x^2

根據公式:a^2 -2a b+b^2 三(a-b)^2

2010-01-31 18:21:03 補充：
多謝chanwaiki4指導!

-xy(x-y)^2+x(y-x)^2-xy(x-y)^2
= -xy(x-y)^2-x(x-y)^2-xy(x-y)^2
=-x(x-y)^2[y-1-y]
=-x(x-y)^2(y-y-1)
=-x(x-y)^2(-1)
=x(x-y)^2

2010-02-01 17:19:41 補充：
chanwaiki4,請問你如何由-xy(x-y)^2+x(y-x)^2-xy(x-y)^2 變為-xy(x-y)^2+x(x-y)^2-xy(x-y)^2?
(y-x)要變(x-y),符號係要轉ga
+(y-x) = -(x-y)
y-x = -x+y
y-x = y-x

2010-02-02 17:28:44 補充：
chanwaiki4,多謝賜教!學到野^^

-xy(x-y)^2+x(y-x)^2-xy(x-y)^2

=-xy(x-y)^2 + x(-1)(x-y)(x-y)(-1) -xy(x-y)^2
=-xy(x-y)^2 + x(x-y)^2 -xy(x-y)^2
=(x-y)(x-2xy)

=(x-y)(x)(1-2y)

2010-02-02 17:49:27 補充：
(y-x)^2 = (y-x)(y-x) = y^2 - 2xy + x^2
(x-y)^2 = (x-y)(x-y) = x^2 - 2xy + y^2 = y^2 - 2xy + y^2

不過我錯左一個位..
=-xy(x-y)^2 + x(x-y)^2 -xy(x-y)^2 呢度應該抽 (x-y)^2
唔知做乜傻左- -] 打打下少左個2次
=(x-y)^2 (-xy+x-xy)
=(x-y)^2 (x-2xy)
=(x-y)^2 (x) (1-2y)