将方程x y分之2-3x-y-搜答案-搜搜考试网

(x+3y)(x-y)/(x-y)(x-y)=x+3y/x-y再问：那当y分之x=3，这个分式的值等于多少?再答：x+3y/x-y=3y+3y/3y-y=6y/2y=3

2x+2y分之3y+x²+xy分之2xy=3y/2(x+y)+2xy/x(x+y)=3y/2(x+y)+2y/(x+y)=7y/2(x+y)如追加其它问题,再问：这道题要通分，能不能化成同分

=(2X/3Y)*(3X/4Y)*(4/xy)=(2x*3x*4)/(3y*4y*xy)=2x/(y^3)

x/y=3x=3y(x²+2xy-3y²)/(x²-xy+y²)=(9y²+6y²-3y²)/(9y²-3y²

因为x-y=4xy所以x-2xy-y=2xy2x+3xy-2y=11xyx-2xy-y分之2x+3xy-2y=5.5

这个不能约分,已经是最简了不能化简

3xy-[2xy-2(xy-2分之3xy)+xy]+3xy=6xy-[2xy-2xy+3xy+xy)=6xy-4xy=2xy=2×3×3分之1=2

xy/(x+y)=2∴xy=2(x+y)(3xy-x-y)/(3x-5xy+3y)=[6(x+y)-x-y]/[3x+3y-10(x+y)]=5(x+y)/[-7(x+y)]=-5/7

因为X+Y分之XY=2,所以XY=2(X+Y)代入后面的分子式得：13（X+Y)/5(X+Y)=13/5

原式=3y/2(x+y)+2xy/x(x+y)=(3xy+4xy)/2x(x+y)=7xy/2x(x+y)=7y/(2x+2y)再问：不对再答：哦，不信就算了

（x+2y-3xy)-(-2x-y+xy)=x+2y-3xy+2x+y-xy=(1+2)x+(2+1)y-(3+1)xy=3x+3y-4xy=3(x+y)-4xy=3*1/2-4*(-1/2)=3/2

原式(-xy/3)²*[xy(2x-y)-2x(xy-y²)]=(x²y²/9)(2x²y-xy²-2x²y+2xy²)

3y/(2x+2y)+2xy/(x²+xy)=3y/(2x+2y)+2y/(x+y)=3y/(2x+2y)+4xy/(2x+2y)=7y/(2x+2y)

x-y分之xy=-3分之1xy分之(x-y)=-3x-y=-3xyx-2xy-y分之2x+3xy-2y=(-6xy+3xy)/(-3xy-2xy)=3/5

急不解决问题最后还是靠自己多动脑看课本其实都是课本上的再问：你看看啊！课本上没有，不会才问的！.........

xy/(x+y)=2(x+y)/xy=1/21/x+1/y=1/2(3x-xy+3y)/(-x+3xy-y)=(3/y-1+3/x)/(-1/y+3-1/x)=[3(1/x+1/y)-1]/[(3-(

中间是÷?再问：不是，写错了，是分解应试再问：（x²分之x²-xy）÷（y分之x-x分之y)再答：这是计算吧，怎么可能是因式分解再问：那你按计算做再答：原式=【x²分之x

若x且y不等于0,则2*x^2-5x*y+3y^2=0等式两边同除以x*y,得2x/y-5+3y/x=0,设x/y=a,则2a-5a+3/a=0,化为二次函数的一般形式：2a^2-5a+3=0,因式分

设x+y=axy=b,则b/a=3b=3a所以-X+3XY-Y分之2X-3XY+2Y可以写成(2a-3b)/(3b-a)=-7/8

令f=x^3+y^2+2xy+3x+5y+1则df=3x^2dx+2ydy+2xdy+2ydx+3dx+5dy=0即(3x^2+2x+3)dx+(2y+2x+5)dy=0于上dy/dx=-(3x^2+