x²-3x+6xy+9y²-9y

若X方-2XY+Y方+1XY-11=0则：x-y=0.而且xy=1所以,x=y=1,或者,x=y=-1所以,x/y=1X方+6XY+9Y方分之X方-25Y方*5X-25Y分之X+3Y=（x²

1.（x-1)^2+2(1-x)=(x-1)(x-1-2)=(x-1)(x-3)2.(x-y)/(x+3y)÷(x^2-y^2)/(x^2+6xy+9y^2)-2y/(x+y）=(x-y)/(x+3y

解题思路：本题主要利用完全平方公式进行因式分解即可求出结果解题过程：解:x²－6xy＋9y²=(x-3y)2

x＾2-3xy／x＾2－6xy+9y＾2=x(x-3y)/(x-3y)^2=x/(x-3y)

Solution:x^2-2xy+3y^2=9(1)4x^2-5xy+6y^2=30(2)Eq(1)*5-Eq(2)*2,wehavex^2-y^2=5(3)Eq(2)-Eq(1),wegetx^2+

1、平方差原式=[(2x+3y)+(x+2y)][(2x+3y)-(x+2y)]=(2x+3y+x+2y)(2x+3y-x-2y)=(3x+5y)(x+y)2、3|x-3|+(x-3y)²=

解题思路：根据题意，由完全平方公式的知识可求解题过程：varSWOC={};SWOC.tip=false;try{SWOCX2.OpenFile("http://dayi.prcedu.com/inc

x^2-6xy+9y^2+x^2y-9y^3=(x-3y)^2+y(x^2-9y^2)=(x-3y)^2+y(x+3y)(x-3y)=(x-3y)(x-3y+xy+3y^2)

方是什么是平方吗再问：嗯再答：=x(2x-3)-3y(2x-3)=(2x-3)(x-3y)

√x^-2xy+y^2+x^2-6xy+9y^2/x-3y=√(x-y)^2+(x-3y)^2/x-3y由于y>x=y-x+x-3y=-2y=-2√5

1.,

-2x+6xy-2y/(7x+5y)-9xy-(3x+y)=[3(x+y)-x-y]/[7x+5y-9/2(x+y)-3x-y]=2(x+y)/[-1/2(x+y)]=-4

y/x=1/3所以x=3y原式=x(3x+y)(3x-y)/(3x+y)(3x-y)²=x/(3x-y)=3y/(3×3y-y)=3y/8y=3/8

[(x-y)/(x+3y)]/[(x^2-y^2)/(x^2+6xy+9y^2)]-xy/(x+y)=(x-y)/(x+3y)*(x+3y)^2/(x-y)(x+y)-xy/(x+y)=(x+3y)/

16524

原式=(x-y)/(x+3y)×[(x+3y)^2/(x+y)(x-y)]-2y/(x+y)=(x+3y)/(x+y)-2y/(x+y)=(x+3y-2y)/(x+y)=(x+y)/(x+y)=1

第一项与第三项先合并9xy(x-y)(x+1)-3y(x-y)(3x+2y)+6y^2*(x-y)(x+1)=(x-y)(x+1)(9xy+6y^2)-3y(x-y)(3x+2y)=(x-y)(x+1

XY/（X+Y）=3,XY=3（X+Y）原式=［6（X+Y）+4XY］/［9（X+Y）+4XY］=［6（X+Y）+12（X+Y）］/［9（X+Y）+12（X+Y）］=［18（X+Y）］/［21（X+Y

原式=-x²y+2xy²+2x²y²-4xy³-3x³+27x³y-18x²y²+2x²y-18x&

因为,x-y=3xy所以：-3x+6xy+3y/[(7x-5y)-9xy-(3x-y)]=[-3(x-y)+6xy]/[(7x-5y)-9xy-(3x-y)]=[-3*3xy+6xy]/[7x-5y-