因式分解：1.ab(c²+d²)+cd(a²+b²)2.(a-b)²-

因式分解：
1.ab(c²+d²)+cd(a²+b²)
2.(a-b)²-a²+b²
3.x(x-1)+y(y+1)-2xy
4.(c²-b+²d²-a²)²-4(ab-od)²
5.a^4+2a³+3a²+2a+1
6.x³-7x+6
7.a²-20a+64
8.(x^4+2)²-9x^4
9.a²-b²+4a+2b+3
10.(x^4+4)²+3x(x²+4)+2x²
11.(x²+3x-2)(x²+3x+4)-16
12.(x+1)(x+2)(x+3)(x+4)+1
这12题,麻烦了```````时间不是很紧,只要晚上解答完即可,分当然也不会少,

1.ab(c^2+d^2)+cd(a^2+b^2)
=abc^2+abd^2+a^2cd+b^2cd
=(abc^2+a^2cd)+(abd^2+b^2cd)
=ac(bc+ad)+bd(bc+ad)
=(bc+ad)(ac+bd)
2.(a-b)^2-a^2+b^2
=(a-b+a)(a-b-a)+b^2
=-b(2a-b)+b^2
=b[b-(2a-b)]
=2b(b-a)
3.x(x-1)+y(y+1)-2xy
=x^2-x+y^2+y-2xy
=(x-y)^2-(x-y)
=(x-y)(x-y-1)
4.(c^2-b^2+d^2-a^2)^2-4(ab-od)^2
=[(c^2-b^2+d^2-a^2)+2(ab-cd)][(c^2-b^2+d^2-a^2)-2(ab-od)]
=(c^2-b^2+d^2-a^2+2ab-2cd)(c^2-b^2+d^2-a^2-2ab+2cd)
=[(c-d)^2-(a-b)^2][(c+d)^2-(a+b)^2]
=(c-d-a+b)(c-d+a-b)(c+d+a+b)(c+d-a-b)
5.a^4+2a^3+3a^2+2a+1
=(a^4+2a^2+1)+(2a^3+2a)+a^2
=(a^2+1)^2+2a(a^2+1)+a^2
=(a^2+1+a)^2
6.x^3-7x+6
=(x^3-1)-7x+7
=(x-1)(x^2+x+1)-7(x-1)
=(x-1)(x^2+x+1-7)
=(x-1)(x^2+x-6)
=(x-1)(x-2)(x+3)
7.a^2-20a+64
=(x-4)(x-16)
8.(x^4+2)^2-9x^4
=(x^4+2+3x^2)(x^4+2-3x^2)
=(x^2+1)(x^2+2)(x^2-1)(x^2-2)
=(x^2+1)(x^2+2)(x+1)(x-1)(x^2-2)
9.a^2-b^2+4a+2b+3
=(a^2+4a+4)-(b^2-2b+1)
=(a+2)^2-(b-1)^2
=(a+2+b-1)(a+2-b+1)
=(a+b+1)(a-b+3)
10.(x^2+4)^2+3x(x^2+4)+2x^2
=(x^2+4+2x)(x^2+4+x)
11.(x^2+3x-2)(x^2+3x+4)-16
=[(x^2+3x)-2][(x^2+3x)+4]-16
=(x^2+3x)^2+2(x^2+3x)-8-16
=(x^2+3x)^2+2(x^2+3x)-24
=(x^2+3x+6)(x^2+3x-4)
=(x^2+3x+6)(x+4)(x-1)
12.(x+1)(x+2)(x+3)(x+4)+1
=[(x+1)(x+4)][(x+2)(x+3)]+1
=[(x^2+5x)+4][(x^2+5x)+6]+1
=(x^2+5x)^2+10(x^2+5x)+24+1
=(x^2+5x)^2+10(x^2+5x)+25
=(x^2+5x+5)^2