已知3x=2y≠0,求分式-搜答案-神马作文网

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

x^2+y^2-6x-8y+25=0x^2-6x+9+y^2-8y+16=0(x-3)^2+(y-4)^2=0∴x=3且y=4y/x-x/y=4/3-3/4=7/12

2x-3y=0所以y=2x/3代入(x^2+xy-y^2)/(2x^2+xy-y^2)得到[x^2+x*2x/3-(2x/3)^2]/[2x^2+x*2x/3-(2x/3)^2]=(x^2+2x^2/

此题做法不止一种,这里给你一个较简单方便的做法如果是填空题,直接把x换成4,y换成3代入即可算出正确答案

1）由1/x-1/y=5,得(y-x)/xy=5,所以y-x=5xy,即x-y=-5xy(3x+5xy-3y)/(x-3xy-y)=[3(x-y)+5xy]/[(x-y)-3xy]=(-15xy+5x

x=-2y(2xy+y^2)/(x^2-xy)=(-4y^2+y^2)/(4y^2+2y^2)=-3y^2/(6y^2)=-1/2再问：我算出来也是-1/2，可答案说是-15/28

=-(x+y)-3/5=-5-3/5=-5.6

x/2=y/3x=2y/3(3x+2y)/(2x-3y)=[3(2y/3)+2y]/[2(2y/3)-3y]=4y/(-5y/3)=-12/5

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）

x-3y=0x=3y2x+y/x^2-2xy+y^2×(x-y)=(2x+y)/(x-y)^2*(x-y)=(2x+y)/(x-y)=(6y+y)/(3y-y)=7y/2y=7/2

x²+3分之x-2y的值为0∵x²+3>0∴x-2y=0∴x=2yx²-y²分之x²-3xy-4y²=(x-4y)(x+y)/(x+y)(x

1.已知：4x^2+12xy+9y^2=0(xy≠0),求分式y/x-x/y的值.4x^2+12xy+9y^2=0(2x+3y)^2=0因为(2x+3y)^2大于等于0所以2x+3y=0x=-3/2y

x-5y=0,x=5y【（3x+y）/（x的2次方-2xy+y的2次方）】×（y-x）=(3x+y)/(y-x)²×(y-x)=(3x+y)/(y-x)=(15y+y)/(y-5y)=-4

x－5y=0x=5y原式=（x-y）平方/（3x+y）(y-x)=(5y-y)平方/（15y+y）(y-5y)=16y平方/-64y平方=-1/4如还有新的问题,请不要追问的形式发送,另外发问题并向我

3X-4y=03x=4yx:y=4:3x=4ay=3a3x²-y²分之x²＋2xy=(16a^2+2x4ax3a)/(3x16a^2-9a^2)=40a^2/39a^2=

x^2-2x+y^2+6y+10=0(x-1)^2+(y+3)^2=0x=1y=-3(x-y)/(x+y)=4/(-2)=-2

3x+2y=0y=-1.5xx/y=x/-1.5x=-2/3y分之3x+3=3x/-1.5x+3=1

∵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

设x/2=y/3=z/-1=ax=2ay=3az=-a(2x+6y-3z)/(x+y+2z)=(4a+18a+3a)/(3a)=25a/3a=25/3