(x的平方分之x-1减x 1)除以4的平方-4x 1分之1-x

[(x-4)/(x^2-1)]÷[(x^2-3x-4)/(x^2+2x+1)]+1/(x-1)=[(x-4)/(x+1)(x-1)]÷[(x-4)(x+1)/(x+1)^2]+1/(x-1)=[(x-

（x+1）/x²-2x²/(x+1)=1两边乘x²(x+1)(x+1)²-2x^4=x²(x+1)x²+2x+1-2x^4=x^3+x

由题意可知x≠0且x≠1且x≠-1原方程两边同乘以x(x+1)(x-1)可得：7(x-1)+3(x+1)=6x7x-7+3x+3=6x10x-4=6x4x=4解得：x=1易知x=1是原方程的增根所以原

(x分之X的平方+4-4)除的X平方+2x分之X的平方-4=[(x²+4)/x-4]÷[(x²-4)/(x²+2x)]=[(x²-4x+4)/x]÷[(x+2)

原式=（x-4）²/（2+x）（2-x）÷（4+x）(4-x)/(x+2)²=（4-x）²/（2+x）（2-x）÷（4+x）(4-x)/(x+2)²=（4-x）

x的平方-y的平方分之x的平方+2xy+y的平方除一x-y分之x的平方+xy,其中x=√2-1,y=√2+1=(x+y)^2/(x+y)(x-y)/((x^2+xy)/(x-y))=(x+y)/(x-

x²－4x＋2＝0由韦达定理得：x1＋x2＝4,x1·x2＝2∴(1)x1+x2+3x1x2=4+3*2=10(2)x2/x1+x1/x2=(x2²+x1²)/x1x2=

5x²+x-5=0两根x1,x2,由韦达定理得x1+x2=-1/5x1x2=-5/5=-1x1²+x2²=(x1+x2)²-2x1x2=(-1/5)²

X1＋X2=-B/A=2X1*X2=C/A=1/2求得X1=1+根号2或者X1=1-根号2从而求出X2的值X1/X2+X2/X1=(X1*X1+X2*X2)/(X1X2)=6

x1+x2=4x1x2=1/2原式=(x1+x2)²÷(x1+x2)/x1x2=x1x2(x1+x2)=2

设x1,x2是方程2x平方+4x-3=0的两个根,则x1+x2=-2x1·x2=-3/2∴x1平方+x2平方=(x1+x2)²-2x1·x2=(-2)²-2×(-3/2)=4+3=

3x的平方+6x－1＝0,韦达定理得：X1+X2=-b/a=-2,X1X2=c/a=-1/31/X1+1/X2=(X1+X2)/X1X2=-2/(-1/3)=63x的平方+6x－1＝0

[(x^2-2x+1)/x^2]÷(x^2-1)*[(x^2+x)/(x^2-3x+2)]=[(x-1)^2/x^2]÷[(x+1)(x-1)]*[x(x+1)/(x-1)(x-2)]=(x-1)^2

2x平方-5x-1=0X平方-5/2X-1/2=0X平方-5/2X=1/2X平方-5/2X+5/4的平方=1/2+5/4的平方（X-5/4）平方=33/16X-5/4=正负根号33/4X=正负根号33

x1+x2=-3/2x1x2=-21/x1+1/x2=（x1+x2)/x1x2=(-3/2)/(-2)=3/4x1²+x2²=(x1+x2)²-2x1x2=(-3/2)&

X1+X2=-6/2=-3X1*X2=-3/21/X1+1/X2=(X1+X2)/(X1X2)=-3/(-3/2)=2

原式=[（x+2）/x（x-2）-（x-1）/（x-2）²]÷（4-x）/x=[（x+2）（x-2）/x（x-2）²-x（x-1）/x（x-2）²]÷（4-x）/x=[（

x1+x2=4x1x2=-1(x1+x2)^2/(1/x1+1/x2)=(x1+x2)^2*x1x2/(x1+x2)=x1x2*(x1+x2)=-4

2x²+5x-3=0（2X-1)(X+3)=0所以有X1=1/2X2=-3或者X1=-3X2=1/2则|x1-x2|=3.51/x1²+1/x2²=4+1/9=37/9