已知y分之x等于2 7,求分式x的平方 2xy-搜答案-拍题作业网

1/X-1/Y=5,去分母得：Y-X=5XY,2x+7xy—2y分之-x+xy+y=[(y-x)+xy]/[-2(y-x)+7xy]=6xy/(-3xy)=-2.

X+Y.X/Y-Y/X=(X^2-Y^2)/(xy)=(x+y)(x-y)/(xy)=x+y

由　1/X-1/Y=5,两边同乘　XY,得出Y-X=5XY,那么　　分子　-X+XY+Y=6XY分母　2X+7XY-2Y=7XY-2(Y-X)=-3XY　　得此分式的值为－2

由　1/X-1/Y=5,两边同乘　XY,得出Y-X=5XY,那么　　分子　-X+XY+Y=6XY分母　2X+7XY-2Y=7XY-2(Y-X)=-3XY　　得此分式的值为－再问：还有一题x+x分之一=

1/x-1/y=2001则(x-xy-y)/(x-y)=2002/2001

[(x-1)/2]-(x/3)=13(x-1)-2x=6x=9√x/(x+2)=3/11

1/x-1/y=2所以得：x-y=-2xy；代入下式(x-2xy-y)/(2x-3xy-2y)=(-2xy-2xy)/(-4xy-3xy)=4/7

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

x分之1-y分之1=5xy分之（y-x）=5y-x=5xy（y-x）分之xy=5xy分之xy=5分之1

1:5/42:7

1/x-1/y=5（y-x）/xy=5y-x=5xyx-y=-5xy（3x+5xy-3y）/（x-3xy-y）=【3×（-5xy）+5xy】/（-5xy-3xy）=-10xy/-8xy=5/4

2x=-yy=-2xxy/(x^2-y^2)=x*(-2x)/[x^2-(-2x)^2]=-2x^2/[x^2+4x^2]=-2x^2/5x^2=-2/5

1、因为原方程有增根（增根使分母为零）,所以增根为x=1或3所以x=1或3为去分母后所得的方程即（x+1）（3-x）=a（x-1)代入解答即可2、设y=x分之2x-1,则2x-1分之x=y分之1原方程

x²-3x=-1即x²+1=3xx+1/x=3

假设x分之3=y分之4=z分之5=1,则x=3,y=4,z=53x-2y+z分之x+y+z=(3x3-2x4+5)分之（3+4+5）=6分之12=2http://zhidao.baidu.com/li

1/x-1/y=2005y-x=2005xy(-x+xy+y)/(2x+6016xy-2y)=[xy+(y-x)]/6016xy-2(y-x)]=(xy+2005xy)/(6016-4010xy)=2

已知：1/X-1/Y=5通分：(Y-X)/XY=5,倒数：XY/(Y-X)=1/5.

x/y+y/x=(x²+y²)/xyx²+y²=(x+y)²-2xy=36-16=20原式=20/8=2.5

y-x=3xyx-y=-3xyx-2xy-y=-5xy2x+3xy-2y=2(x+y)+3xy=-6xy+3xy=-3xy分式x-2xy-y分之2x+3xy-2y=5/3

y=4x带入3x-y=3x-4x=-xx+y=x+4x=5x(x+y)/(3x-y)=5x/(-x)=-5