已知x分之1-y分之1=3,则x-xy-y分之5x xy-5y的值为
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由1/x-1/y=3得(y-x)/xy=3题中的式子分子分母同时除以xy得(2/y+3-2/x)/(1/y-2-1/x),通分得【2(x-y)/xy+3】/【(x-y)/xy-2】代入得3/5
已知x分之1-y分之1=3,则有y-x=3xy(5x+xy-5y)/(x-xy-y)=7/2
(5x+3xy-5y)/(x-2xy-y)=(5/y+3-5/x)/(1/y-2-1/x)分子分母同时除以xy=[-5(1/x-1/y)+3]/[-(1/x-1/y)-2]=(-15+3)/(-3-2
1、1/x-1/y=3(y-x)/xy=3y-x=3xyx-y=-3xy原式=[3(x-y)+xy]/[(x-y)-xy]=[3(-3xy)+xy]/[(-3xy)-xy]=-8xy/(-4xy)=2
1/x-1/y=(y-x)/xy=3y-x=3xy所以x-y=-3xy所以原式=[(x-y)-2xy]分之[2(x-y)-5xy]=[(-3xy)-2xy]分之[2(-3xy)-5xy]=(-5xy)
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
令2分之x=3分之y=4分之z=k,则:x=2ky=3kz=4kx+y+z=1/12,得:2k+3k+4k=1/129k=1/12k=1/108所以:x=2/108=1/54y=3/108=1/36z
1/x-1/y=3(y-x)/(xy)=3y-x=3xy(x-2xy-y)/(2x+3xy-2y)=[-(y-x)-2xy]/[-2(y-x)+3xy]=(-3xy-2xy)/(-6xy+3xy)=5
∵3x-2y分之5x+y=2分之1∴(5x+y)×2=(3x-2y)×1【两边同乘以2(3x-2y),即交叉相乘】∴10x+2y=3x-2y∴10x-3x=2y+2y∴7x=4y.(1)原式x+y分之
1.令x/2=y/3=z/4=k,则有:x=2ky=3kz=4k所以:(2x+y-z)/(x+y+z)=(2×2k+3k-4k)/(2k+3k+4k)=1/32因为x^2+y^2+2x+4y+4=0即
∵x/4=y/5 ∴x:y=4:5 ∵y/5=z/3 ∴y:z=5:3 ∴x:y:z=4:5:3
在1/x+1/y=3的两边分别乘以xy,则y+x=3xy.将此代入所求的式子,有(3*3xy+xy)/(3xy-xy)=5比反了,抱歉啊!
x:y=2分之1:3分之1=3:2y:z=2:3,所以x:y:z=3:2:3再问:已知x:y=1.5:1,y:z=3分之2:6分之5,求x:y:z,谢谢再答:采纳我,重新问
x分之3=y分之1x=3yy分之1=z分之2z=2yxy+yz+zx分之2x²-2y²+5z²=[2(3y)²-2y²+5(2y)²]/(3
1/x+1/y=5(x+y)/x*y=5x+y=5*x*yx+2xy+y=x+y+2xy=5xy+2xy=7xy2x-3xy+2y=10xy-3xy=7xy(2x-3xy+2y)/(x+2xy+y)=
因为:3分之x+1=4分之y+3=5分之x+y,所以:(x+1)/3=(y+3)/4=(x+y)/54x+4=3y+94x=3y+55x+5=3x+3y2x=3y-5x=5y=5则x+2y+3分之3x
x分之1-y分之1=-3所以(y-x)/xy=-3y-x=-3xy从而3x-2xy-3y分之x+3xy-y=(3xy+3xy)/(3×3xy-2xy)=6/7
x分之1-y分之1=3(y-x)/xy=3y-x=3xy(2x+3xy-2y)/(x-2xy-y)=[3xy-2(y-x)]/[-2xy-(y-x)]=(3xy-6xy)/(-2xy-3xy)=(-3
原式等价于10(x+1)=5(y+3)=4(x+y)10(x+1)=5(y+3)可得2x-y=15(y+3)=4(x+y)可得4x-y=15解得x=7y=13x+2y+3=363x+2y+1=48两式