x²-5xy-6xy²=0,则x y=?

13x^2-6xy+y^2-4x+1=09x²-6xy+y²+4x²-4x+1=0(3x-y)²+(2x-1)²=0∵(3x-y)²≥0&n

由y=3xy+x得x-y=-3xy2x+5xy-2y/x-2xy-y=2（x-y）+5xy/x-y-2xy=-6xy+5xy/-3xy-2xy1/5

2x^2+5xy-3y^2=0(2x-y)(x+3y)=0y=2x或者x=-3y当y=2x时(x^2-y^2)/xy=x/y-y/x=1/2-2=-3/2当x=-3y时(x^2-y^2)/xy=x/y

x-5xy+6y=0(√x-2√y)(√x-3√y)=0所以√x=2√y,√x=3√yx=4y或x=9y原式=(8y)/(9y)=8/9或=(14y)/(20y)=7/10

5xy+4x+7y+6x-3xy-4xy+3y=5xy-3xy-4xy+4x+6x+7y+3y=（5-3-4）xy+（4+6）x+（7+3）y=-2xy+10x+10y=-2xy+10（x+y）因为x

解(x+1)平方+/y-1/=0∴x+1=0,y-1=0∴x=-1,y=1∴2(xy-5xy平方)-(3xy平方-xy)=(2xy+xy)+(-10xy平方-3xy平方)=3xy-13xy平方=3×(

解题思路：将原方程右边分解因式为（x-4y)(x+y)=0,可得x=4y或x=-y,进而可求出x与y的比值。解题过程：解：∵x2-3xy-4y2=0∴（x-4y)(x+y)=0∴x=4y或x=-y∵x

x=-1,y=-6或x=6,y=1代入式子得x^2-xy^2=37或30x^2y+xy^2=-42或42

6x^2-5xy-6y^2=0即(2x-3y)(3x+2y)=0亦即2x-3y=0或3x+2y=0得x,y满足在这两条过(0,0)的直线即可.

x+根号xy-6y=0(根号x-2根号y)(根号x+3根号y)=0解得根号x=2根号y即x=4y或根号y+3根号y=0不成立所以4x+5根号xy-6y分之x+2根号xy=[4y+2根号(4y*y)]/

先把代数式（5XY+4X+7Y)+(6X-3XY)-(4XY-3Y)化简（5XY+4X+7Y)+(6X-3XY)-(4XY-3Y)=5XY+4X+7Y+6X-3XY-4XY+3Y=-2XY+10X+1

第1小题：x²y-xy²=xy(x-y)=6(5)=30第2小题：(x+y)²=x²+y²+2xy=x²+y²-2xy+4xy=(

（7xy+4x-7y）+(6x-3xy)-(3y+4xy)=7xy+4x-7y+6x-3xy-3y-4xy=10x-10y=10（x-y）=10*3=30

(5xy+4x+7y)+(6x-3xy)-(4xy-3y)=5xy+4x+7y+6x-3xy-4xy+3y=(5xy-3xy-4xy)+(4x+6x)+(7y+3y)=-2xy+10x+10y=-2x

因为xy/（x+y）=1/2所以x+y=2xy原式=3（x+y)-5xy/(-x-y+3xy)=3*2xy-5xy/(-2xy+3xy)=xy/xy=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

lg(xy)=0xy=1则:|x|＝1而Y=X,|x|不等于Y所以x=-1,y=-1原式=log8（2）=1/3

13x^2-6xy+y^2-4x+1=09x^2-6xy+y^2+4x^2-4x+1=0(3x-y)^2+(2x-1)^2=03x-y=0,2x-1=0,x=0.5y=3*0.5=1.5(xy-x^2

x+y=5xy（2x-3xy+2y)/(x+2xy+y）=[2（x+y）-3xy]/[(x+y)+2xy]=(2×5xy-3xy)/(5xy+2xy)=7xy/7xy=1再问：若x＋1/x＝3,求(x

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-