已知x y=3,则分式x-y x y=作业帮
来源:学生作业帮助网 编辑:作业帮 时间:2024/05/16 04:40:26
1/x+1/y=3∴x+y=3xy3x-2xy+3y/x+xy+y=[3(x+y)-2xy]/[(x+y)+xy]=(9xy-2xy)/(3xy+xy)=7/4
代入方法:分母:3x-3xy+3y=3(x+y)-3xy=3•(3xy)-3xy=9xy-3xy=6xy分子:x+xy+y=x+y+xy=3xy+xy=4xy所以原式=6xy/4xy=3/
已知1/x-1/y=3,应该是1/x+1/y=3,[按原式得不出结果!]如此,则3xy=x+y(3x-xy+3y)/(x+xy+y)=2
1/x-1/y=3等号左边通分,得(y-x)/(xy)=3故x-y=-3xy代入分式[2x+3xy-2y]/[x-2xy-y]=[2(x-y)+3xy]/[(x-y)-2xy]=(-6xy+3xy)/
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
∵正数x,y满足2x+y-3=0,∴3=2x+y.∴x+2yxy=13(2x+y)(1y+2x)=13(5+2xy+2yx)≥13(5+22xy•2yx)=3,当且仅当x=y=1时取等号.则x+2yx
首先化简通分1/x+1/y=5得:(x+y)/xy=5即有x+y=5xy将要求的分式化简:3x+xy+3y/x-2xy+y=3x+3y+xy/x+y-2xy(根据加法交换律)=3(x+y)+xy/(x
2x+3y=53y=5-2xy=(5-2x)/33x^2+12xy+y^2=3x^2+12x(5-2x)/3+(5-2x)^2/9x=4时=48-48+1=1
1/x-1/y=3同时乘以xyy-x=3xyx-y=-3xy(2x-3xy-2y)/(x-2xy-y)=[2(x-y)-3xy]/[(x-y)-2xy]=(-6xy-3xy)/(-3xy-2xy)=(
因为:1/x-1/y=3(y-x)/xy=3x-y=-3xy(1)又因为:(2x+3xy-2y)/(x-2xy-y)=[2(x-y)+3xy]/[(x-y)-2xy]代入(1)得:(-6xy+3xy)
y=3x/5原式=x/(x+3x/5)+(3x/5)/[x-3x/5]-(9x^3/25)/(x^3-9x^3/25)=8/3-3/2-9/16=29/48
(x-2xy-y)/(2x+3xy-2y)分子分母同时除以xy,得:=[(1//y-1/x)-2]/[(2/y-2/x)+3]=[-(1/x-1/y)-2]/[-2(1/x-1/y)+3]=(-3-2
(1)XxX+yxy=(x+y)^2-2xy=4^2+2*12=16+28=44(2)XxXxy+Xxyxy=xy*(x+y)=4*(-12)=-48不懂可追问,有帮助请采纳,谢谢!
[2x+14xy-2y]/[3x-2xy-3y]=(2/y+14-2/x)/(3/y-2-3/x)分子分母同时除以xy=[-2(1/x-1/y)+14]/[-3(1/x-1/y)-2]=(-6+14)
xy/x+y=1/2xy=2(x+y)3x-xy+3y/x-xy+y=[3(x+y)-2(x+y)]/[(x+y)-2(x+y)]=(x+y)/[-(x+y)]=-1
|3-y|+|x+y|=0,且|3-y|≥0,|x+y|≥0,所以3-y=0,x+y=0,所以y=3,x=-3.所以x+yxy=-3+3-3×3=0-9=0.答:x+yxy的值为0.
分式2x+3yxy中,x、y的值都扩大到原来的2倍,则分式的值缩小为原来的12,故选:B.
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)=
∵x-y/xy=3∴x-y=3xy2x+3xy-2y/x-2xy-y=[2(x-y)+3xy]/[(x-y)-2xy]=(6xy+3xy)/(3xy-2xy)=9xy/(xy)=9