(12 (X-6)×3-9) 1900 1981 X=?

|x-1|+|x-10|表示数轴上x到1的距离+x到10的距离.显然最小值是9,此时x只要在1到10之间就好.类似的,|x-2|+|x-9|的最小值是7,此时x在2到9之间就好.|x-3|+|x-8|

=x^18+x^15+x^12+x^9+x^6+x^3+1+x^3-1+5-4分解因式把下面的18换成21就是了=(x^18+1)+(x^15+1)+(x^12+1)+(x^9+1)+(x^6+1)+

1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x+13x+14x+15x=550120x=550x=55/12=4.583

x(1+2+...+9)=x(9-8-7-...-1)x=0记得采纳啊

(1/x^2+3x+2)+(1/x^2+5x+6)+(1/x^2+7x+12)+(1/x^2+9x+20)=1/(x+1)(x+2)+1/(x+2)(x+3)+1/(x+3)(x+4)+1/(x+4)

x+9x=6x*2+1212x-x-9x=-122x=-12x=-12÷2x=-6x+9-x/3=4两边乘33x+9-x=123x-x=12-92x=3x=3÷2x=3/2

中间错了原式=(x+2)/(x-3)(x+2)+2x/x(x-3)-(x+1)/(x-3)²=1/(x-3)+2/(x-3)-(x+1)/(x-3)²=3/(x-3)-(x+1)/

化简得2/x^2+6x=0,即（1+3x^3)/x^2=0,所以x=-（1/3)^(1/3)

15x=23x-248x=24x=312+5x=3x-82x=-20x=-103(x-3)=9-(x+6)4x=9+9-6=12x=34+x=4x-173x=21x=7

原式=3(X-3)/[2(X-3)(X+2)]-(X-3)/[(X-2)(X-3)]+2X/[(X+3)(X-3)]=3/[2(X+2)]-1/(X-2)+2x/[(X+3)(X-3)]=(X-10)

原式=(x+2)/(x+2)(x-3)-2x/x(x-3)-(x+1)/(x-3)²=1/(x-3)-2/(x-3)-(x+1)/(x-3)²=-1/(x-3)-(x+1)/(x-

(x+2)/(x^2-x-6)+2x/(x^2-3x)-x/(x^2-6x+9)=(x+2)/[(x-3)(x+2)]+2x/[x(x-3)]-x/[(x-3)^2]=1/(x-3)+2/(x-3)-

原式=1/(x+1)(x+2)+1/(x+2)(x+3)+1/(x+3)(x+4)+1/(x+4)(x+5)=1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)+1/(x+3)-1/(x+

应该是-2x²,不是-3x²3x²-x=1原式=9x^4-3x³+15x³-5x²+3x²-7x+2001=3x²(3x

【不好意思,题目太难让我想了很久】储备知识：x^n-y^n=(x-y)【x^(n-1)+x^(n-2)y+x^(n-3)y²+……+x²y^(n-3)+xy^(n-2)+y^(n-

1/(x^2+3x+2)+1/(x^2+5x+6)+1/(x^2+7x+12)+1/(x^2+9x+20)＝1/﹙x＋1﹚﹙x＋2﹚＋1/﹙x＋2﹚﹙x＋3﹚＋1/﹙x＋3﹚﹙x＋4﹚＋1/﹙x＋4﹚

设x^3=a,则题目可变为下式:a^3+a^2+a-14=a^3-8+a^2+a-6=(a-2)(a^2+2a+4)+(a-2)(a+3)=(a-2)(a^2+2a+4+a+3)=(a-2)(a^2+

①x8x1(x+8)(x+1)②x-3x-3(x-3)^2③x3x-4(x+3)(x-4)④x3x7(x+3)(x+7)⑤x5x-25(x+5)(x-25)⑥x12x3(x+1)(2x+3)

分步写,好让看的清楚符号[√(x^2-6x+9)/x^2-x-12]=√(x-3)^2/(x-4)(x+3）=（x-3)/(x-4)(x+3）；(x^3-16x)/(x^2-3x)=x(x^2-16)

1/x^2-3x+2-1/x^2-5x+6-1/x^2-7x+12-1/x^2-9x+20=1/(x-1)(x-2)-1/(x-2)(x-3)-1/(x-3)(x-4)-1/(x-4)(x-5)=1/