已知x分之y=2,则x-y分之x-

3/x-2/y=3等式两边同乘以xy3y-2x=3xy(2x-3y-xy)/(7xy+9y-6x)=[-(3y-2x)-xy]/[3(3y-2x)+7xy]=(-3xy-xy)/[3·(3xy)+7x

设2分之x-y=3分之y-z=七分之z+x=K,则X-Y=2K,Y-Z=3K,X+Z=7K,解得：X=6K,Y=4K,Z=K,根据题意得：X+Y+Z=22,6K+4K+K=22K=2,∴X=12,Y=

y=[x/(x-2)-x/(x+2)/2x/(2-x)=4x/(x-2)(x+2)*(2-x)/2x=-2/(x+2)y的值是整数,x+2=1,-1,2,-2x=,-1,-3,0,-4

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

(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

2x-y分之x+y=2,则2x-y=2(x+y)4x-2y分之x+y-4x+4y分之2x-y=2(2x-y)分之x+y-4(x+y)分之2x-y=4(x+y)分之x+y-4(x+y)分之2(x+y)=

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

2/3

解原式=2(x-y)/(x+y)-(x+y)/3(x-y)=6(x-y)(x-y)/[3(x+y)(x-y)]-(x+y)x+y)/[3(x-y)(x+y)]=5(x-y)(x-y)/[(x+y)(x

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

因为x+y分之2x-y=2又因为x+y分之4x-2y是它的2倍所以x+y分之4x-2y就=4因为x+y分之2x-y=2倒过来2x-y分之x+y就为1/2又2x-y分之4x+4y是2x-y分之x+y的4

x+y分之x-y=2求x+y分之3x-3y减x-y分之2(x+y)的值x+y分之x-y=2x-y=2(x+y)(x+y)分之(3x-3y)-(x-y)分之2(x+y)的值x+y分之3x-3y=(x+y

∵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

y分之x减y=x/y-1=3/4-1=-1/4有什么不明白可以对该题继续追问请及时选为满意答案,

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

5x=-3yx=-3|5y直接带进去得答案,或者=2\3x-2|3x+2|x+y的和乘（x+y）除以x-y|x=2乘x\x-y=2（-3\5y）\（-3\5y-y）=3\4手机果然不行.

(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

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