Question

数学，因式分解(m-n)^2-(m+n)^2

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

=x(x+y)(x-y-x-y)怎么得的
题目打错了 (x-y)^2-(x+y)^2

Answer 1

用平方差公式a^2-b^2=（a+b）(a-b),把x-y看成a，把x+y看成b
原式=（x-y+x+y）（x-y-（x+y））
=2x*（-2y）
=-4xy

Answer 2

(x-y)^2-(x y)^2
=[(x-y) (x y)][(x-y)-(x y)]
=[x-y x y][x-y-x-y]
=(2x)(-2y)
=-4xy
PS:空白处为加号 不懂请追问!学习进步^_^

追问

x（x+y)(x-y)-x(x+y)这道题呢，说清每部

追答

我知道了!
x(x y)(x-y)-x(x y)
=x(x y)[(x-y)-(x y)]
=x(x y)(x-y-x-y)
=-2xy(x y)
望采纳!

Answer 3

=(x-y+x+y)(x-y-x-y)
=2x(-2y)
=-4xy
运用平方差公式

追问

x（x+y)(x-y)-x(x+y)这道题

追答

=x^3-xy^2-x^2-xy

Answer 4

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

=(x-y+x+y)(x-y-x-y)
=(2x)(-2y)
=-4xy

追问

(x-y-x-y)怎么得的

追答

(x-y)-(x+y)