2x y=103x-y=5怎么做
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xy/x+y=3则xy=3(x+y)2x-5xy+2y/x-3xy+y=2(x+y)-5xy/(x+y)-3xy=2(x+y)-15(x+y)/(x+y)-9(x+y)=-13(x+y)/-8(x+y
x-y=2xy3x-5xy-3y/x+xy-y=[3(x-y)-5xy]/[(x-y)+xy]=(6xy-5xy)/(2xy+xy)=1/31/x+1/y=4y+x=4xyx-5xy+y/2x+xy+
(3xy+10y)+[+5x-(2xy+2y-3x)]=3xy+10y+[+5x-2xy-2y+3x],[原式去括号]=3xy+10y+5x-2xy-2y+3x,[去括号]=3xy-2xy+5x+3x
-xy(x^2y^5-xy^3-y)=-(xy^2)^3+(xy^2)^2+xy^2=-(-2)^3+4-2=8+4-2=10
=xy(x-y)×[-xy/(x-y)]=-(xy)²=-x²y²
原式=[4(x+y)-2xy]分之[(x+y)+xy]=[4(3xy)-2xy]分之[(3xy)+xy]=10xy分之2xy=5分之1
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
(5x-xy+5y)/(3xy-x-y)=[5(x+y)-xy]/[3xy-(x+y)]=[5(x+y)-2(x+y)]/[6(x+y)-(x+y)]=1/2
两式相加得x=4+xy即x=4/(1-y)①两式相减得y=-1-4xy②①代入②y=-1-4y*4/(1-y)整理得y²-16y-1=0解得y=8±√65代入①,即可算出x了如有不明白,可以
x-y=7,则x=y+7,代入XY=(X-5)(Y-2),得:(y+7)y=(y+2)(y-2),即:y^2+7y=y^2-4,移项,合并同类项得:7y=-4,则y=-4/7,故x=y+7=45/7.
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
(x-y)/(2x+2y)=(x-y)/2(x+y)=(x-y)(x+y)/2(x+y)^2xy/(x+y)^2=2xy/2(x+y)^2x-y/2x+2y=(x^2-y+4xy)/2x=(x^2-y
xy/(x+y)=2xy=2(x+y)(3x-5xy+3y)/(-x+2xy-y)=[3(x+y)-5xy]/[2xy-(x+y)]=[3(x+y)-10(x+y)]/[4(x+y)-(x+y)]=-
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2xy+x+y=83所以4xy+2x+2y=83*2所以(2x+1)(2y+1)=165=3*5*11=1*165=3*55=5*33=11*15所以2x+1=1,2y+1=165或2x+1=3,
1.(1/x)-(1/y)=5(2x+5xy-2y)/(x-2xy-y)分子,分母除以xy得(2/y+5-2/x)/(1/y-2-1/x)=(2*5+5)/(-5-2)=-15/72.(x+m)/(x
原式=-xy²(x²y^4-xy²-1)∵xy²=-2原式=2((-2)²-(-2)-1)=10