计算:[(x y)乘(x-y)]乘3x-搜答案-搜搜做题作业网

等于1/X*（X-Y）

刚刚算反了

我写纸上

原式=[(x+2y)(x-2y)/(x+y)²]÷[(x+2y)/x(x+y)]=(x+2y)(x-2y)x(x+y)/[(x+y)²(x+2y)]=(x-2y)x/(x+y)=(

这是一个初中竞赛题目与高中的主要运用公式x^3-y^3=(x-y)(x^2+xy+y^2)x^3+y^3=(x+y)(x^2-xy+y^2)其中(x-y)(x^2+xy+y^2)=x(x^2+xy+y

(-2x^2y^3)^2(xy)^3=4x^4y^3*x^3y^3=4x^(4+3)*y^(3+3)=4x^7y^6

3xy[2xy-x(y-2)+x-1]=3xy(2xy-xy+2x+x-1)=3xy(xy+3x-1)=3x^2y^2+9x^2y-3xy

3xy[2xy-x（y-2）+x]＝3xy[2xy-xy+2x+x]=3xy(xy+3x)=3x²y²+9x²y

(X+Y)(X^2-XY+Y^2)=(x*x^2-x*xy+x*y^2)+(x^2y-xy^2+y^3)=x^3+y^3这个是立方和的公式,再给你一个x^3-y^3=(X-Y)(X^2+XY+Y^2)

这题少括号了吧.

【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

（xy-y^2)÷x-y/xy=y(x-y)×[xy/(x-y)]=xy²

[(x²+2xy+y²)/(xy-y²)][(x²-2xy+y²)/(xy+y²)]={(x+y)²/[y(x-y)]}{(x-y

=x^3-y^3-(x^3+y^3)=-2y^3^3表示三次方

直接分开相乘结果为xy（x^-1)+xy(y^-1)]=x+y

（xy-x²）乘（x-y）分之xy=-x(x-y)乘[(x-y)分之xy]=-x²y

X²+2xy+y²/xy乘x²-2xy+y²/xy+y²=(x+y)²/xy×(x-y)²/y(x+y)=(x+y)(x-y)&#

（-4xy）乘（xy+3x²y）=-4x²y²-12x³y²

3x平方乘(-2xy立方)=-6x立方y立方

x-y/xy-y^2计算

解(x-y)/(xy-y²)=(x-y)/y(x-y)=1/y