若x+y=3.xy=负1-搜答案-搜搜做题作业网

将一式变形可得（x方-y方）/xy=1x方y负方等于1加x/y（左右同除y方即可）y方x负方等于1减y/x（同理）将其带入二式中可得2+x/y-y/x通分得2加（x方-y方）/xy所以等于3

[XY(2X-Y)的平方-(-XY的二次方)的二次方]除以8XY=[(2x-y)²-xy³]÷8=[（-2/3-1）²+1/3*1]÷8=（25/9+1/3）÷8=28/

(x-y+x+y)/(x^2-y^2)*((x-y)^2/2x)=2x/(x-y)(x+y)*((x-y)^2/2x)=(x-y)/(x+y)x=根号3,y=负根号2原式=（根号3+根号2）/（根号3

x+（xy-4x）-3y=x-4x-3y+xy=-3(x+y)+xy=1-3=-2

由题设可知y=xy-1，∴x=yx3y=x4y-1，∴4y-1=1，故y=12，∴12x=x，解得x=4，于是x+y=4+12=92．故答案为：92．

x^2-y^2=xy两边同除以xy得：x/y-y/x=1xy^-1-x^-1y=1再问：解分式方程（1）7/2+(900-3x/1.2x)=900/x(2)(100/2a)+1/2=(300/2a)+

=3x平方y-2x平方y+6xy-3x平方y+xy=-2x平方y+7xy=-2*1*(-2)+7*(-1)*(-2)=4+14=18

∵xy(x+y)^-1=1,yz(y+z)^-1=2,xz(z+x)^-1=3∴(x+y)/xy=1,(y+z)/yz=1/2,(x+z)/xz=1/3即1/x+1/y=1,1/y+1/z=1/2,1

(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)=-2xy+2x+3y-3xy-2y+2x-x-4y-xy=-6xy+3x-3y=-6xy+3*(x-y)当时,原式=-6*1+3*

x+y=-1两边同时平方得x²+2xy+y²=(-1)²(x²+y²)+2xy=1代入xy=-5得(x²+y²)+2×(-5)=1

x+y=3xyx^4+y^4+2(xy)^2=9(xy)^2x^4+y^4=7x^2y^2xy的负二次方+x的负二次方y=x^2/y^2+y^2/x^2=x^4+y^4/x^2y^2=7

依题意知：（x-1）（y+1）=-1,化解得：xy+x-y-1=-1,x-y=-xy,两边同时除以xy得：1/y-1/x=-1

x（x+y）（x-y）-x（x+y）²=x(x+y)(x-y-x-y)=-2xy(x+y)=-2*(-1/2)*1=1

解-1/3x(xy²+y+x³y的4次方)=-1/3x[(xy)y+y+(xy)³×y]=-1/3x(y+y+y)=-1/3x*3y=-xy=-1

[y+1/x+1]+[x+1/y+1]=(y+1)^2/(x+1)(y+1)+(x+1)^2/(x+1)(y+1)=[(Y+1)^2+(x+1)^2]/(x+1)(y+1)=[y^2+2y+1+x^2

1.xy不等于0,所以x^2-y^=xy两边各除xy得x/y-y/x=1所以2+xy负一次方-x负一次方y=32.已知X的m-2次方幂*X的3m次方幂=X的6次方幂所以m-2+3m=6,得m=21/2

=xy(1-2y^2)=-0.119616

Cx-1/y=2x才对（因为x=-1/y）而x是绝不会等于0的

x-2y=15两边平方x^2-4xy+4y^2=225x^2+4y^2=225+4xy=225+4*(-25)=125所以x^2+4y^2-1=125-1=124

原式有意义要求y≠0且(x-1)y≥0等号右边为非正数,左边符号与y有关,说明y≤0又由前分析y≠0,则y