x-y分之2x 2y与xy分之(x y)方 通分
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1/(x-y)=(x+y)/(x²-y²)(xy+y²)/(x²-y²)=(xy+y²)/(x²-y²)
最简二次根式的是根号5(a²-b²)根号x²+y²,
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
通分为分母是(x+y)⒉(x-y),即为2xy(x-y)/(x+y)⒉(x-y)和x(x+y)/(x+y)⒉(x-y)
原式=2x2y+2xy-3x2y-3xy-4x2y=-5x2y-xy当x=-2,y=12时,原式=-9.
绝对算不出来再答:如果是一道题发图咯再问:x平方减xy加y平方分之x平方加2xy加y平方他给你条件是y分之x等于2分之1xy再问:吧xy无视掉再答:马上再答:化成Y等于2X在带入再问:然后怎么样再答:
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
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
原式=4x2y-6xy+3(4xy-2)+x2y+1=5x2y+6xy-5当x=2,y=-12时,原式=5×4×(-12)+6×2×(-12)-5=-21.
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
最简公分母是2(x+y)²(x-y)/2x+2y=(x-y)/2(x+y)=(x-y)(x+y)/2(x+y)²xy/(x+y)²=2×xy/2(x+y)²=2
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
3y/(2x+2y)+2xy/(x²+xy)=3y/(2x+2y)+2y/(x+y)=3y/(2x+2y)+4xy/(2x+2y)=7y/(2x+2y)
3y与2y²的最简公分母是6y²3y分之x=x/(3y)=(2y×x)/(2y×3y)=(2xy)/(6y²)2y平方分之3x=3x/(2y²)=(3×3x)/
由已知条件可得:x-y=-4xy,(也就是在等式两边乘xy后整理,即可),代入所求的式子里分母为-4xy+7xy,即3xy;分子为-4xy-2xy,即-6xy,化简得-2
解(1):最简公分母是6(x+5)3分之x=x/3=2x(x+5)/[6(x+5)]6分之1-x=(1-x)/6=(1-x)(x+5)/[6(x+5)]x+5分之x平方-x=(x²-x)/(
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-(
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
原式=2x2y+2xy-3x2y+3xy-4x2y=-5x2y+5xy,当x=-1,y=1时,原式=-5×(-1)2×1+5×(-1)×1=-5-5=-10.
公分母是2(x+y)^2(x-y)/(2x+2y)=(x-y)*(x+y)/2(x+y)*(x+y)=(x^2-y^2)/2(x+y)^2xy/(x+y)^2=2xy/2(x+y)^2