y平方-2x分之2y-xy

原式=2xy/(x+y)(x-y)+x(x-y)/(x+y)(x-y)=(2xy+x²-xy)/(x+y)(x-y)=(x²+xy)/(x+y)(x-y)=x(x+y)/(x+y)

(x-y)/(x+y)=(x-y)(x+y)/[(x+y)^2]=(x^2-y^2)/[x^2+y^2+2xy]=2xy/[x^2+y^2+x^2-y^2]=2xy/(2x^2)=y/xx^2-y^2

（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)

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

x/y=7/2(x²-3xy+2y²)/(x²+2xy+y²)=[(x/y)²-3(x/y)+2]/[(x/y)²+2(x/y)+1]=[(

=(x-2y)(x-y)/(x-y)²=(x-2y)/(x-y)再问：做完啊。。。。。。再答：好了呀这个不可以再化简了，是一个最简分式了再问：刚刚不小心题目打掉了，你在看已知Y分之X等于7分

（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^

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)

y分之x=2分之1y=2x所以原原式=(x²-2x²-8x²)分之（x²＋4x²＋4x²）=-9分之9=-1

x平方-3xy+2y平方=0(x-2y)(x-y)=0x=2yx=y(1)x=2y则xy分之x平方+y平方的值=((2y)^2+y^2)/(2y*y)=(4y^2+y^2)/(2y^2)=5/2(1)

原式(-xy/3)²*[xy(2x-y)-2x(xy-y²)]=(x²y²/9)(2x²y-xy²-2x²y+2xy²)

(2分之1x平方y—2xy+y平方）*3xy=1/2x²y*3xy-2xy*3xy+y²*3xy=3/2x³y²-6x²y²+3xy&sup

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

2y-xy分之x的平方-2x=x（x-2）/y(2-x)=-x/y;很高兴为您解答,skyhunter002为您答疑解惑如果本题有什么不明白可以追问,

原式=(x+y)*x²/(x-y)(x+y)+y²/(x-y）-2xy（x-y)/(x-y)²=(x²+y²)/(x-y)-2xy/(x-y）=（x-

还有下面这种方法7x平方-y平方分之x平方-2xy+3y平方分子分母同时除以y²=[(x/y)²-2(x/y)+3]/[7(x/y)²-1]=(4/9-4/3+3)/(2

(x+y)/(x-y)=3/2[(x/y)+1]/[(x/y)-1]=3/23(x/y)-3=2(x/y)+2x/y=5y/x=1/5(x^2+y^2)/xy=x/y+y/x=5+1/5=26/5

y分之x=2分之1y=2x所以原原式=(x²-2x²-8x²)分之（x²＋4x²＋4x²）=-9分之9=-1

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