y=-0.1x y=x分之2那些表示y是x的正比例函数-搜答案-智慧作业帮

原式=（2x+y）/（5xy-6xy）×（1/2）（x+2y）=（x+y）/（-xy）×（1/2）（x+y）=（-xy）/（2x+2y）=（-xy）/2(x+y)=（1/2）×（-xy）/(x+y)当

3x²+xy-2y²=0(x+y)(3x-2y)=0x=-y,或3x=2yy/x=-1,或3/2x/y-y/x-(x²+y²)/(xy)=x/y-y/x-x/y

(x-y)/(x+y)=(x-y)(x+y)/[(x+y)^2]=(x^2-y^2)/[x^2+y^2+2xy]=2xy/[x^2+y^2+x^2-y^2]=2xy/(2x^2)=y/xx^2-y^2

-5分之2

x/y=3x=3y(x²+2xy-3y²)/(x²-xy+y²)=(9y²+6y²-3y²)/(9y²-3y²

XY-2Y二次方分之X二次方-2XY=Y(X-2Y)分之X(X-2Y)约分=Y分之X

因为x-y=4xy所以x-2xy-y=2xy2x+3xy-2y=11xyx-2xy-y分之2x+3xy-2y=5.5

3xy-[2xy-2(xy-2分之3xy)+xy]+3xy=6xy-[2xy-2xy+3xy+xy)=6xy-4xy=2xy=2×3×3分之1=2

1/x+1/y=-2则(x-xy+y)/(x+xy+y)分子分母同除以xy=(1/x+1/y-1)/(1/x+1/y+1)=(-2-1)/(-2+1)=3

xy/(x+y)=2∴xy=2(x+y)(3xy-x-y)/(3x-5xy+3y)=[6(x+y)-x-y]/[3x+3y-10(x+y)]=5(x+y)/[-7(x+y)]=-5/7

因为X+Y分之XY=2,所以XY=2(X+Y)代入后面的分子式得：13（X+Y)/5(X+Y)=13/5

(xy-x²)÷(x²-2xy+y²)/(x-y)×(x-y)/x²=-x(x-y)÷(x-y)²/x²=-x(x-y)×x²/(

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

x-y分之xy=-3分之1xy分之(x-y)=-3x-y=-3xyx-2xy-y分之2x+3xy-2y=(-6xy+3xy)/(-3xy-2xy)=3/5

xy/(x+y)=2(x+y)/xy=1/21/x+1/y=1/2(3x-xy+3y)/(-x+3xy-y)=(3/y-1+3/x)/(-1/y+3-1/x)=[3(1/x+1/y)-1]/[(3-(

(x+y)/(x-y)=3/2[(x/y)+1]/[(x/y)-1]=3/23(x/y)-3=2(x/y)+2x/y=5y/x=1/5(x^2+y^2)/xy=x/y+y/x=5+1/5=26/5

x^2-y^2=2xy,得x/y-y/x=2,即（y/x)^2+2(y/x)-1=0∴y/x=-1+√2或y/x=-1-√2(舍去,因为x,y都是正数).即（x-y)/(x+y)=√2-1

x-1分之y= 分之xy-y

分子上应写：（x-1）²或者x²-2x+1再问：怎么书面表达呢？能否详细一些，谢谢再答：希望你及时采纳！！！！！

∵x-y=4xy∴原式=[2(x-y)+3xy]/[-(x-y)-2xy]=(8xy+3xy)/(-4xy-2xy)=11xy/(-6xy)=-11/6