x 2y x-2y分之4y的平方

x^2-y^2=(x+y)(x-y)30=4/3*(x-y)x-y=30*3/4x-y=45/2

[（x的平方+y的平方）-（x-y)的平方+2y(x-y)]/4y=1(x²+y²-x²+2xy-y²+2xy-2y²)/4y=1(4xy-2y

1-（x-y）/(x+2y)÷(x²-y²)/(x+2y)²=1-(x-y)/(x+2y)×(x+2y)²/(x+y)(x-y)=1-(x+2y)/(x+y)=

x平方+y平方+8x+6y+25=0(x+4)²+(y+3)²=0∴x=-4;y=-3∴(x²-4y²)/(x²+4xy+4y²)-x/(x

3x^2+xy-2y^2=(3x-2y)(x+y)=0x=-2y/3,或x=-y但由于你要求的式子中分母里有X平方-Y平方x=-y舍去其他就代入吧

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（x的平方-y的平方)分之2xy+(x+y)分之x-(y-x)分之y=（x的平方-y的平方)分之2xy+(x+y)分之x+(x-y)分之y=(x²-y²)分之[2xy+x(x-y)

前者分子：x^2-y^2=(x+y)(x-y)那前面这项就可以化简约分啦后者分子：4x^2-4xy+y^2=(2x)^2-2*2xy+y^2=(2x-y)^2建议你理解一下x^2-2xy+y^=(x-

=-(x+2y)(x-2y)/(x+y)²×2x(x+y)/(x-2y)=-2x(x+2y)/(x+y)=-(2x²+4xy)/(x+y)

（x分之x-y）-（y分之x+y）+（2xy分之x的平方-y的平方）=1-y/x-1-x/y+(x^2-y^2)/2xy=-2(y^2+x^2)/2xy+(x^2-y^2)/2xy=-(x^2+3y^

4y的平方-2y+5的值是72y²-y=13分之4y的平方-3分之2y+15=3分之2﹙2y²-y)+15=3分之2+15=15又3分之2

x的平方+2xy+y的平方分之x的平方-4y的评方÷x的平方+xy分之x+2y=(x+2y)(x-2y)/(x+y)²×x(x+y)/(x+2y)=x(x-2y)/(x+y)=(x²

x平方+y平方+2xy分之x平方-4y平方除以x平方+xy分之2y+x=(x-2y)(x+2y)/(x+y)²·x(x+y)/(x+2y)=x(x-2y)/(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=[2x/(x-y)]*[y/(x+y)]-[x^4/(x^4-y^4)]/[x^2/(x^2+y^2)]^2=2xy/(x^2-y^2)-(x^2+y^2)^2/[(x^2+y^2)(x^2-y

x+2y+4y^2/(x-2y)-4x^2y/(x-4y^2)=x+2y+4y^2/(x-2y)-4x^2y/[(x+2y)(x-2y)]通分,分母为[(x+2y)(x-2y)]=(x+2y)(x+2

由题意可得：4x-3y=3x-2y或4x-3y=2y-3x解得：x=y或7x=5y所以x/y=1或5/7

（Y-X)/4x(y-1)-y(x-1)=4推出Y-X=42分之x的平方加y的平方推出X的平方/4+Y的平方=4

X平方+4Y的平方=4XYx^2-4xy+4y^2=0(x-2y)^2=0x=2yX-Y分之X+2Y=(2y+2y)(2y-y)=4y/y=4

x-y分之2x的平方-y-x分之x的平方-4xy+x-y分之2y的平方-x的平方=2x/(x-y)-(x²-4xy)/(y-x)+(2y-x²)/(x-y)=(2x+x²