x=3x 3.18,求X解

∵x2+x-1=0，∴x2+x=1，2x3+3x2-x=2x（x2+x）+x2-x=2x+x2-x=x2+x=1．

f(x)'=3x^2-3f(x)'=3x^2-3>=0时x>=1或x

X³-3X=X(X²-3)=X(X+√3)(X-√3)

f(x-1)=x(x-1)(x-2)=[(x-1)+1](x-1)[(x-1)-1]所以f(x0=(x+1)x(x-1)=x³-x再问：请问第二步是怎么转换来的表示看不懂--再答：凑x-1采

x-3/4x=181/4x=18x=18/(1/4)x=18乘4x=6436+0.6X=420.6X=42-360.6X=6x=103/5x=1/3x=1/3乘5/3x=1/5(/这个为分数线,望采纳

y=(m-1）x2(m-2）x-1仿照线相交于点O仿照f（x）=xlnx（a-1）x2y-x=4

x3-3x2-11x+8=x（x2-3x)-11x+8=x-11x+8=-10x+8

∵x2+3x-1=0，∴x2+3x=1，x3+5x2+5x+18=x（x2+3x）+2x2+5x+18=x+2x2+5x+18=2（x2+3x）+18=2+18=20．

3.3X-1.2X4=8.4　　3.3X-4.8=8.4　　3.3x=8.4-4.8　　3.3x=3.6　　x=12/11　　18÷2X=3　　18=6x　　x=3

x1x2x3x3x1x2x2x3x1c1+c2+c3x1+x2+x3x2x3x1+x2+x3x1x2x1+x2+x3x3x1r2-r1,r3-r1x1+x2+x3x2x30x1-x2x2-x30x3-

增广矩阵=21-1113-21-3414-35-2r2-r1-r3,r1-2r30-75-950-75-9514-35-2r2-r1,r1*(-1/7),r3-4r101-5/79/7-5/70000

f(x)=1/3x3-x2-3x+3f‘(x)=x2-2x-3令f'(x)=0得x=3,x=-1所以x=3时f(x)取极大值-6x=-1时f(x)取极大值4又2/3

2x3-3x+三分之二x3-2x-三分之四x3+x-1=4/3x3-4x-1=4/3x(-1/2)3＋4x1/2-1=-4/3x1/8+2-1=1-1/6=5/6

y'=3x^2-6x+6=3(x^2-2x+2)=3[(x-1)^2+1]>0y'>0函数f(x)=X3-3X+6X-6在R上单调递增

x+y=1(x+y)^2=x^2+2xy+y^2=1(x+y)^3=x^3+y^3+3xy(x+y)=1而x^3+y^3=1/3,代入得：3xy=2/3xy=2/9由于x=1-y;故代入xy=2/9;

∵1+x+x2+x3=0，∴x+x2+x3+…+x2004=x（1+x+x2+x3）+x5（1+x+x2+x3）+x9（1+x+x2+x3）+…+x1997（1+x+x2+x3）+x2001（1+x+

x+x2+x3+…+x2000=（x+x2+x3+x4）+（x5+x6+x7+x8）+…+（x1997+x1998+x1999+x2000）=x（1+x+x2+x3）+x5（1+x+x2+x3）+…+

x^2-3x+1=0x^2+1=3xx+1/x=3(x+1/x)^2=9x^2+2+1/x^2=9x^2+1/x^2=7x^3+1/x^3=(x+1/x)(x^2-1+1/x^2)=3x(7-1)=1

y=x³-6x²+12x-8-x³=-6x²+12x-8=-6(x-1)²-2所以x=1,y最大=-2

由y=x3及y=x+2图像知F(x)=x3-x-2=0有唯一解x=a,且x0F(1)=-2F(2)=4F(1.5)=-0.125F(1.75)≈1.609F(1.63)≈0.701F(1.57)≈0.