已知2x³ xy=6,3y² 2xy=9-搜答案-搜搜做题作业网

x/y=2x=2yx²-xy+3y²/x²+xy+6y²=4y^2-2y^2+3y^2/4y^2+2y^2+6y^2=5y^2/12y^2=5/12

因为x/y=2所以x=2y是[x^2-xy+3y^2]/[x^2+xy+6y^2]吧=(4y^2-2y^2+3y^2)/(4y^2+2y^2+6y^2)=5y^2/12y^2=5/12

原式=3xy+6y-xy+6x=2xy+6(x+y)=2*(-2)+6*4=24-4=20

(1)已知x+y=6,xy=-3x^2y+xy^2=xy(x+y)=-3*6=-18(2)x*[2-(1/x)]+(x/x^2-2x)*(x^2-4)=x*(2x-1)/x+[x/x(x-2)]*(x

原式=((x/y)^2-x/y+3)/((x/y)^2+x/y+6)代入x/y=2=(2^2-2+3)/(2^2+2+6)=(4-2+3)/(4+2+6)=5/12其实只要将（x^2-xy+3y^2）

因为已知x/y=2,所以x=2y代入算式得：（4y*y-2y*y+3y*y）/(4y*y+2y*y+6y*y)化简原式=5/12

/>∵1/x=1/y=6∴x=y=1/6∴(3x-2xy+3y)/(3xy+x+y)=(3/6-2*1/6*1/6+3/6)/(3*1/6*1/6+1/6+1/6)上下同乘36=(18-2+18)/(

“x愚人国度”您好,很高兴为您解答!x^2y+xy^2=xy(x+y)=-3*6=-18

x^2y+xy^2=xy(x+y)=-3*6=-18

3（xy+2y）-（xy-6x）=3xy+6y-xy+6x=2xy+6(x+y)=2×(-2)+6×4=-4+24=20

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

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

x-y=3（x-y)^2=9x^2-2xy+y^2=9x^2+y^2=13（x+y）（x-y）-y^2-（6x^2y-2xy^2)/2y=x^2-y^2-y^2-3x^2+xy=-2(x^2+y^2)

2(x+xy)-[(xy-3y)-x]-(-xy)=2x+2xy-xy+3y+x+xy=3x+3y+2xy=3（x+y）+2xy=3*（-2）+2*3=0

∵x-y=4xy，∴2x+3xy-2yx-2xy-y=2(x-y)+3xyx-y-2xy=8xy+3xy4xy-2xy=112．故答案为：112．

xy/x+y=6∴xy=6(x+y)3x-2xy+3y/-x+3xy-y=[3x-12(x+y)+3y]/[-x+18(x+y)-y]=-9(x+y)/17(x+y)=-9/17再问：你在啊？再答：在

因为xy(y^2+y)-y^2（xy+2x）-3xy=xy^3+xy^2-xy^3-2xy^2-3xy=-xy^2-3xy根据x+y=4,x-y的绝对值=6,可以写出两个方程组x+y=4,x-y=6和

已知x+xy=-2,xy-y=-6则X+Y=42x｛-4y-3[（x+xy）²+x]-½[（y-xy）²-2y]=2x｛-4y-3[（-2）²+x]-&fr

(x+y)(x-y)-y²+(x-y)²-(6x²y-2xy²)÷(2y)=x²-y²-y²+x²-2xy+y²

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