(1)(x+y)^2-(x+y)^3

问题描述:

(1)(x+y)^2-(x+y)^3
(2)(x-y)-(x-y)^3
(3)(x-y)^2-(y-x)^3
(4)2(x-y)-3(y-x)^2
(5)4ab(a=b)^2-6a^2b(a+b)
(6)(x+y)^2(x-y)+(x+y)(x-y)^2
(7)2a(a-3)^2-6a^2(3-a)+8a(a-3)
(8)24xy^2z^2(x+y-z)-32xyz(z-x-y)^2+8xy(z-x-y)
(9)(a-b)(b-a)^n(b-a)^2n-1 [两解)
(10)2^2=3,2^b=6,2^c=12,求a,b,c之间的一个数量关系[两解)

(1)(x+y)^2-(x+y)^3
=(x+y)^2-(x+y)(x+y)^2
=(1-x-y)(x+y)^2
(2)(x-y)-(x-y)^3
=(x-y)-(x-y)(x-y)^2
=(1-x+y)(x-y)^2
(3)(x-y)^2-(y-x)^3
=(y-x)^2-(y-x)(y-x)^2
=(1-y+x)(y-x)^2
(4)2(x-y)-3(y-x)^2
=2(x-y)-3(x-y)^2
=2(x-y)-3(x-y)(x-y)
=(2-3x+3y)(x-y)
(5)4ab(a=b)^2-6a^2b(a+b)
=4ab(a+b)(a+b)-6aab(a+b)
=2ab(a+b)(2a+2b-3a)
=2ab(a+b)(2b-a)
(6)(x+y)^2(x-y)+(x+y)(x-y)^2
=(x+y)(x+y)(x-y)+(x+y)(x-y)(x-y)
=(x+y)(x-y)(x+y+x-y)
2x(x+y)(x-y)
(7)2a(a-3)^2-6a^2(3-a)+8a(a-3)
=2a(a-3)(a-3)+6aa(a-3)+8a(a-3)
=2a(a-3)(a-3+3a+4)
2a(a-3)(4a+1)
(8)24xy^2z^2(x+y-z)-32xyz(z-x-y)^2+8xy(z-x-y)
=24xyyz^2(x+y-Z)-32xyz(x+y-z)(x+y-z)-8xy(x+y-z)
8xy(x+y-z)[3yz^2-4z(x+y-z)-1]这题你的式子可能写错了
(9)(a-b)(b-a)^n(b-a)^2n-1 [两解)
(a-b)(b-a)^n 和 (b-a)^2n-1之间是不是少了个+或-?
你可以分n是偶数和奇数两种情况做,不难
(10)2^2=3,2^b=6,2^c=12,求a,b,c之间的一个数量关系[两解)
由题知道2^a*4=2^b*2=2^c=12
即2^(a+2)=2^(b+1)=2^c
所以a+2=b+1=c