(x y)^2(x-y)怎么做-搜答案-拍题作业网

8（x²-2y²)-x(7x+y)+xy=8x²-16y²-7x²-xy+xy=x²-16y²=(x+4y)(x-4y)

xy(-2xy^2)-2x^2y^3(y^2-1)=-2x^2y^3-2x^2y^5+2x^2y^3=-2x^2y^5再问：能讲下么。。。谢谢了。我会给分的。。再答：再问：xy(-2xy^2)-2x^

X=3y代入后面的公式

最后一项是否多了一个y?如果没有那个y,就应当是(xy-1)²+(x+y-2)(x+y-2)=（xy-1+x+y-2）（xy-1-x-y+2）=(xy+x+y-3)(xy-x-y+1)再问：

对.前提是x不等于y

=xy(x-y)×[-xy/(x-y)]=-(xy)²=-x²y²

【x²+xy/（x-y）】/【xy/（x-y）】=【x²（x-y）/（x-y）+xy/（x-y）】/【xy/（x-y）】={【x²（x-y）+xy】/（x-y）}/【xy

4/e^2隐函数求导dy/dx=-y/(x-e^y)x=e^2/2时,y=2

最简公分母是xy(x-y)∴2x+2y/x-y=xy(2x+2y)/xy(x-y)(x+y)²/xy=(x+y)²(x-y)/xy(x-y)再问：那么x-y/2x+2y与xy/（x

第一个式子上下同乘x-y得2x平方y-2xy平方/（x+y)(x平方-y平方）第二个式子上下同乘x+y得x平方y/（x+y)(x平方-y平方）分母一样了

原式=7x²y+2yx²-2xy²+y²x-3xy²=9x²y-4xy²3x²y-5xy²=-2x²

4x^3-4x^2y+2x^2-2xy=4x^3+2x^2-4x^2y-2xy=2x^2(2x+1)-2xy(2x+1)=2x(2x+1)(x-y)

x平方+xy-2y平方+2x+7y-3=(x-y)(x+2y)+2x+7y-3用待定系数法(x-y+m)(x+2y+n)=(x-y)(x+2y)+n(x-y)+m(x+2y)+mn=(x-y)(x+2

9x2-6xy+y2+4x2-4x+1=0(3x-y)2+(2x-1)2=02x-1=03x-y=0X=0.5Y=1.5

（x-y+1)(x-y-1)

（x-y)/(2x+2y)=(x-y)/2(x+y)=(x-y)(x+y)/2(x+y)^2xy/(x+y)^2=2xy/2(x+y)^2x-y/2x+2y=(x^2-y+4xy)/2x=(x^2-y

因为2xy+x+y=83所以4xy+2x+2y=83*2所以(2x+1)(2y+1)=165=3*5*11=1*165=3*55=5*33=11*15所以2x+1=1,2y+1=165或2x+1=3,

1.(1/x)-(1/y)=5(2x+5xy-2y)/(x-2xy-y)分子,分母除以xy得(2/y+5-2/x)/(1/y-2-1/x)=(2*5+5)/(-5-2)=-15/72.(x+m)/(x

原式={[(x-y)^2+4xy]/(x-y)}{[(x+y)^2-4xy]/x+y}={[x^2-2xy+y^2+4xy]/(x-y)}{[x^2+2xy+y^2-4xy]/x+y}={[x^2+2