作业帮先化简再求值x平方减y平方分之2y减x减y分之一
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/06 16:25:35
原式=(x²+y²+2xy)(x²+y²-2xy)/(x+y)²=(x+y)²(x-y)²/(x+y)²=(x-y)&#
(x-y)分之(x²+y²)+(y-x)分之(2x-y),其中x=3+√2,y=3-√2=(x²+y²)/(x-y)-(2x-y)/(x-y)=(x²
因为x=1+根号2y=1减根号2所以xy=1+根号2乘以1减根号2=1-2=-1x+y=2所以可以求得,原式=xy/(x+y)=-1/2
2x分之1减x+y分之1*（x的平方减y的平方+2x分之x+y）=2x分之1减x+y分之1*【（x+y）*（x-y）+2x分之x+y】=2x分之1-【x+y分之1*（x+y）*（x-y）+x+y分之1
[1/(x-y)-1/(x+y)]÷2y/(x^2-2xy+y^2)=[(x+y)/(x+y)(x-y)-(x-y)/(x+y)(x-y)]÷2y/(x-y)^2=[(x+y-x+y)/(x+y)(x
(xy-x的平方）除以xy分之x的平方-2xy+y的平方乘x的平方分之x-y=x(y-x)*xy/(x-y)²*（x-y）/x²=-y再问：不好意思，打错了(xy-y的平方）除以x
y的平方-xy分之(x+y)的平方÷{-（x-y）的平方分之y的平方+xy}=(x+y)²/[y(y-x)]÷[-y(y+x)/(x-y)²]=(x+y)²/[y(x-y
x²-4y²分之x+2y=[(x-2y)(x+2y)]分之x+2y=x-2y分之1=5-2*3.5=-2
原式=(9x³-xy²)/[(3x+y)(9x²-6xy+y²)]=x(9x²-y²)/[(3x+y)(3x-y)²]=x(3x+
5x²-(3y²+5x²)-(4x²+7xy)=5x²-3y²-5x-²4x²-7xy=-4x²-3y
(2x+y)(2x-y)(4x平方+y平方)=(4x^2-y^2)(4x^2+y^2)=16x^4-y^4=16*（1/2）^4-(1/3)^4=80/81
X平方+Y平方-2X+4Y+5=0=>(x-1)^2+(y+2)^2=0=>x=1,y=-2（2x+y）（2x+y)-(2x-y)平方=8xy=-16
(3x²-xy)/(9x²-6xy+y²)=x(3x-y)/(3x-y)²=x/(3x-y)带值；=2/(6-3)=2/3
(1)(x²-y²)/(x²-2xy+y²)=(x-y)(x+y)/(x-y)²=(x+y)/(x-y)x²＋y²－2x－6y＋1
x+1/2=0,y-1=0x=-1/2,y=1原式=4x²y-(6xy-8xy+4-x²y)+1=4x²y-(-2xy+4-x²y)+1=4x²y+2
原式=(x²-4y²-x²-4xy-4y²)×(2/y)=(-8y²-4xy)×(2/y)=-16y-8x=-4+8=4
解(y²-xy)/(x²-y²)=y(y-x)/(x+y)(x-y)=-y/(x+y)(2x²-2y²)/(x²+2xy+y²)=