1.4(x+5)(x+6)(x+10)(x+12)-3x·x

来源：学生作业帮编辑：大师作文网作业帮分类：数学作业时间：2024/11/11 00:21:58

1.4(x+5)(x+6)(x+10)(x+12)-3x·x
2.xy(x·x-y·y)+yz(y·y-z·z)+zx(z·z-x·x)
3.2x·x+3xy-2y·y-x+8y-6
最好有写过程

1.
4(x+5)(x+6)(x+10)(x+12)－3x^2
= 4*[(x+5)(x+12)][(x+6)(x+10)] - 3x^2
= 4*(x^2 + 60 + 17x)(x^2 + 60 + 16x) - 3x^2
= 4*[(x^2+60)^2 + 33x(x^2+60) + 272x^2)] - 3x^2
= 4(x^2+60)^2 + 132x(x^2+60) + 1085x^2
= [2(x^2 +60) + 35x][2(x^2 +60) + 31x]
= (2x^2 + 35x + 120)(2x^2 + 31x + 120)
= (2x^2 + 35x + 120)(2x + 15)(x+8)
2.
xy(x^2-y^2)+yz(y^2-z^2)+zx(z^2-x^2)
=x^3y-xy^3+y^3z-yz^3+z^3x-zx^3
=x^3(y-z)+y^3(z-x)+z^3(x-y)
因为x-y=(x-z)+(z-y),所以：
=x^3(y-z)+y^3(z-x)+z^3[(x-z)+(z-y)]
=(x^3-z^3)(y-z)+(y^3-z^3)(z-x)
=(x-z)(x^2+xz+z^2)(y-z)+(y-z)(y^2+yz+z^2)(z-x)
=(x-z)(y-z)(x^2+zx+z^2-y^2-yz-z^2)
=(x-z)(y-z)(x-y)(x+y+z)
3.
x^2+3xy-2y^2-x+8y-6
=(x+2y)(2x-y)-x+8y-6
=(x+2y)(2x-y)-(x-8y)-6
=(x+2y-2)(2x-y+3) （十字相乘法）
[也可用待定系数法令(x+2y)(2x-y)-(x-8y)-6=(x+2y+a)(2x-y+b) }

1.4(x+5)(x+6)(x+10)(x+12)-3x·x |X-1|+|X-2|+|X-3|+|X-4|+|X-5|+|X-6|+|X-7|+|X-8|+|X-9|+|X-10| 1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550 (2x^-5x+2/6x^+13x+6)*(6x^-5x-6/6x^-17x+10)*(12x^+8x-15/2x^-x x/x-3-5x/x^2-x-6计算 y=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)(x-10)的导数在x=1 设函数f(x)=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)(x-10), 计算（x*x+4x+5）/（x+2）-（x*x+6x+10）/（x+3）+1 (x-2)(x-3)+2(x-5)(x+6)-3(x^2-7x+12) x+2x+3x+4x+5x+6x+7x+8x+9x=9x-8x-7x-6x-5x-4x-3x-2x-x.x等于多少? 用递归法求y=x-(x*x*x/3!)+(x*x*x*x*x/5!)-(x*x*x*x*x*x*x/7!)+. (x