若x-y=6,xy=36分之17,则代数式x的立方y-2x平方y平方 xy立方
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若X方-2XY+Y方+1XY-11=0则:x-y=0.而且xy=1所以,x=y=1,或者,x=y=-1所以,x/y=1X方+6XY+9Y方分之X方-25Y方*5X-25Y分之X+3Y=(x²
x+y+3=0,x+y=-33分之2-2x-2y+(-x-y)的平方=【2-2(x+y)+(x+y)^2】/3=(2-6+9)/3=5/3(x+y)/xy=3,x+y=3xy(2x-3xy+2y)/(
原式=(2x+y)/(5xy-6xy)×(1/2)(x+2y)=(x+y)/(-xy)×(1/2)(x+y)=(-xy)/(2x+2y)=(-xy)/2(x+y)=(1/2)×(-xy)/(x+y)当
1/x+1/y=2则(2x+3xy+2y)/(x-xy+y)分子分母同除以xy=(2/x+2/y+3)/(1/x+1/y-1)=(4+3)/(2-1)=7
1、1/x-1/y=3(y-x)/xy=3y-x=3xyx-y=-3xy原式=[3(x-y)+xy]/[(x-y)-xy]=[3(-3xy)+xy]/[(-3xy)-xy]=-8xy/(-4xy)=2
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
1/x+1/y=-2则(x-xy+y)/(x+xy+y)分子分母同除以xy=(1/x+1/y-1)/(1/x+1/y+1)=(-2-1)/(-2+1)=3
1.已知x+y=-4,xy=3,求5(xy/2+2y)+[6x-(2xy+y-3x)]的值5(xy/2+2y)+[6x-(2xy+y-3x)]=5xy/2+10y+6x-2xy-y+3x=xy/2+9
(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
1/x-1/y=(y-x)/xy=1y-x=xy(3y-xy-3x)/(x-xy-y)=(3y-y+x-3x)/(x-y+x-y)(2y-2x)/(2x-2y)=-1
原式=(2x-4xy-2y+xy)/(x-2xy-y)=2+xy/(x-2xy-y)xy/(x-2xy-y)的倒数等于1/y-2-1/x=-5,所以xy/(x-2xy-y)=-1/5,原式=2-1/5
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
1.若x分之1-y分之1=2,则求x-xy-y分之3x+xy-3y=0的值.若x分之1-y分之1=2变形(y-x)/xy=2,(y-x)=2xy(3x+xy-3y)/(x-xy-y)=[3(x-y)+
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-(
1/x-1/y=3(y-x)/xy=3y-x=3xy分式的分母=x-2xy-y=(x-y)-2xy=-5xy分子=2x+3xy-2y=2(x-y)+3xy=-3xy所以原式=3/5
把括号打开7X+4Y+XY-5Y-6X+6XY=X-Y+7XY=5+7*(-3)=-16
(7x+4y+xy)-6(六分之五y+x-xy)=7x+4y+xy-5y-6x+6xy=x-y+10xy把x-y=5和-xy=3代入x-y+10xy=5+10*(-3)=5-30=-25所以原式的值是
y=1+1/x=1+1/(1+y)y-1=1/(1+y)(y-1)(1+y)=1y²-1=1y²=2y=±√2再问:不对,答案没一个符合,这是选择题:A.-1B.1+xC.-xD.
1/x-1/y=3(y-x)/xy=3y-x=3xy所以x-y=-3xy原式=[2(x-y)+3xy]/[(x-y)+2xy]=[2(-3xy)+3xy]/[(-3xy)+2xy]=-3xy/(-xy
分子上应写:(x-1)²或者x²-2x+1再问:怎么书面表达呢?能否详细一些,谢谢再答:希望你及时采纳!!!!!