已知x十y=1,xy=5分之一,求x的2次方y xy的平方
来源:学生作业帮助网 编辑:作业帮 时间:2024/05/18 09:34:46
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)/
(3x-5xy+3y)/(x+xy+y)分式上下同除xy,得,(3/y-5+3/x)/(1/y+1+1/x)=1/3再问:太给力了,你的回答完美解决了我的问题!
x-3xy-Y分之3x+5xy-3y==(3x+5xy-3y)/(x-3xy-Y)=(5+3*(1/y-1/x))/(-3+(1/y-1/x)).分子分母同时除以xy=(5-21)/(-3-7).将x
根号内必须大于等于0故有x-1≥0且1-x≥0即x≥1且x≤1所以x=1将x=1代回去得y=3然后将x,y代入所求式即可你的所求式表述不是很清楚,所以没办法帮你求了
1/2x²+xy+1/2y²=1/2(x²+2xy+y²)=1/2(x+y)²=1/2
∵x分之1-y分之1=3∴y分之1-x分之1=-3(x-2xy-y)分之(3x-5xy-3y)分子分母同时除以xy得=(y分之1-2-x分之1)分之(x分之3-5-y分之3)=[(y分之1-x分之1)
由已知得:xy=-1,1/x-1/y=(y-x)/(xy)=5那么:y-x=5xy=-5所以:(y-x)²=25即:y²-2xy+x²=25得:y²+x
x+y=6两边同时平方得x²+2xy+y²=36把xy=-2代入上式得x²+y²=401/x²+1/y²=y²/(x²y
1/x+1/y=(x+y)/xy=4/3
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
因为(x+1/y)(y+1/x)=xy+1+1+1/xy=18+2=20所以y+1/x=20/5=4再问:哦再问:我没想到,,,,
1/x+1/y=(x+y)/xy=5x+y=5xy所以原式=[2(x+y)-3xy]÷[(x+y)+2xy]=[2(5xy)-3xy]÷[(5xy)+2xy]=7xy÷7xy=1再问:1/x+1/y=
1/x+1/y=(x+y)/xy=5==>x+y=5xy所以2x-3xy+2y=2(x+y)-3xy=2*5xy-3xy=7xyx+2xy+y=5xy+2xy=7xy所以2x-3xy+2y除以x+2x
3x-3y=xy3/x-3/y=1(两边同除xy)1/x-1/y=1/3
x^2y+xy^2=xy(x+y)=1/5(x^2+1)(y^2+1)=(xy)^2+x^2+y^2+1=(xy)^2+(x+y)^2-2xy+1=1/25+1-2/5+1=41/25再问:(X的平方
已知(x-5)的平方十|y十2|=o则x-5=0y+2=0则x=5,y=-2则xy=-10
1/x-1/y=2(y-x)/xy=3y-x=3xyx-y=-3xy原式=[2(x-y)-14xy]/[(x-y)-2xy]=[2(-3xy)-14xy]/[(-3xy)-2xy]=-20xy/(-5
选择题最好的方法:设X=2,Y=1或X=-2,Y=-1,则1/X+1/Y=1/2+1=1.5或1/X+1/Y=-(1/2+1)=-1.5