x平方-4y平方分之x 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)=

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

【x-y-(x-y分之4y平方)】【x+y-(x+y分之4x平方)】除以【3(x+y)-x-y分之8xy】=（x-y-x+4y)(x+y-x-4x/y)/(3x+3y-x-8x)=3y*(y-4x/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)

做这样的题要会把分子分母分解因式,最好分解完.这需要有扎实的分解因式的功夫,看到像x^2-y^2这样的式子要敏感,给你几个等式要会把它们用活：x^2-y^2=(x+y)(x-y),x^3-y^3=(x

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)

已知5x-4y=0,切xy≠0,x/y=4/5;求(x平方-y平方)分之(x平方+y平方)-(x-y)分之(x+y)的值=(x²+y²)/(x²-y²)-(x+

若是：①4x²-y²和②X/(3Y-6X),则公分母是3(y-6x)；若是：①1/(4x²-y²)和②X/(3Y-6X),①=1/[(2x-y)(2x+y)],

因为x²+y²-4x+2y+5=0所以(x²-4x+4)+(y²+2y+1)=0所以(x-2)²+(y+1)²=o所以x=2y=-1所以下面

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

=[(x+2y)(x-2y)+4y²]/(x-2y)-4x²y/(x+2y)(x-2y)=x²/(x-2y)-4x²y/(x+2y)(x-2y)=(x³

由椭圆方程可知,a^2=4,b^2=3,所以c^2=1,所以焦点坐标是（c,0）,（-c,0）,即（-1,0）和（1,0）,焦距=2x^2=1/4y类比x^2=2py焦点坐标(0,1/16),准线方程

(8x^2/9y^2)*(3y/-4x)=-2x/3y不懂请追问,满意请采纳~再问：过程？？？？再答：就相当于（8x的平方除以-4x）乘以(3y除以9y的平方）=-2x乘以3y分之一=负的3y分之2x

(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)/(2y)=X^2-y^2-y^2+X^2+y^2-2xy-3x^2+xy=-x^2-y^2-xy=-(x^2+y^2+xy-3

a²=m²+12b²=4-m²c²=a²+b²=16c=4所以焦距=2c=8

原式=[(2x-y)²/(2x+y)]/(2x+y)(2x-y)=(2x-y)/(2x+y)²=(2x-y)/(4x²+4xy+y²)

2(x平方-6分之7y）平方分之（x-3分之2y)平方

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