要使xy分之x y有意义-搜答案-搜狗做题网

x小于0,y小于0,第三象限

∵xy/(a＋b)＝1/15∴a＋b＝15xy同理：b＋c＝17xya＋c＝16xy∴xy/(a＋b＋c)＝xy/[1/2(2a＋2b＋2c)]＝xy/[1/2(a＋b＋b＋c＋a＋c)]＝xy/[1

1）若x,y同为正数,则x分之|x|+y分之|y|+xy分之|xy|=1+1+1=32）若x,y同为负数,则x分之|x|+y分之|y|+xy分之|xy|=-1-1+1=-13）若x,y异号,比如x为正

=(xy-x的平方）除以(x的平方-2xy+y的平方\xy)乘以(x-y\x的平方)=-x（x-y）×xy/（x-y）2×（x-y）/x2=-y再问：嗯

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

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

x分之xy算分式吗?

不算,x有可能等于0

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

1除以（1-根号下xy)

原式(-xy/3)²*[xy(2x-y)-2x(xy-y²)]=(x²y²/9)(2x²y-xy²-2x²y+2xy²)

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

（xy-x²）乘（x-y）分之xy=-x(x-y)乘[(x-y)分之xy]=-x²y

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-(

设x+y=axy=b,则b/a=3b=3a所以-X+3XY-Y分之2X-3XY+2Y可以写成(2a-3b)/(3b-a)=-7/8

xy分之【x加y】等于2分之一xy=2(x+y)【xy加x加y】分之xy=2(x+y)/[2(x+y)+x+y]=2(x+y)/[3(x+y)]=2/3

（xy-x²）÷xy分之x²-2xy+y²乘x²分之x-y=-x(x-y)×xy/(x-y)²×(x-y)/x²=-y∴结果与x的值没有关系

-xy+xy等于多少?

得0=(-X+X)y=0×y=0

干什么?计算吗?原式=x/y(x²-y²)/(xy)-(xy-y²)/(xy-x²)=(x²-y²)/(xy)-y(x-y)/[x(y-x)

[(xy-2)(-xy-2)-4(xy-1)^2]除以(-xy)=[-x²y²+4-4(x²y²-2xy+1)]÷(-xy)=(-x²y²+