作业帮[(x y)(x-y)-(x-y) 2y(x-3y)其中x=1,y=-2
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/28 09:07:08
(x+1)(y+1)
x/(xy-y²)=x/[y(x-y)]y/(x²-xy)=y/[x(x-y)]∴公分母为：xy(x-y)通分后得x/(xy-y²)=x²/[xy(x-y)]y
求数学达人来解答x²/xy-x/y=(1-x)/y3x/4x+y-x-2y/4x+y=(3x-x-2y)/(4x+y)(1-y/y+x)÷x/y²-x²=(1-y)*(y
对.前提是x不等于y
(x+y-2xy)(x+y-2)+(1-xy)^2=(x+y)^2-2(1+xy)(x+y)+4xy+1-2xy+x^2y^2=(x+y)^2-2(1+xy)(x+y)+(1+xy)^2=(x+y)^
xy-1+x-y=XY+X-Y-1(加法交换律）=（XY+X）－（Y＋1）＝X（Y＋1）－(Y+1)（提取公因式X）=(Y+1)(X-1)（提取公因式Y+1）这样可以么?
=xy(x-y)×[-xy/(x-y)]=-(xy)²=-x²y²
这题少括号了吧.
x²＋y－xy－x＝﹙x²－xy﹚＋﹙y－x﹚＝x﹙x－y﹚－﹙x－y﹚＝﹙x－y﹚﹙x－1﹚
【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
1-x-y+xy=(1-x)-(y-xy)=(1-x)-y(1-x)=(1-x)(1-y)
原式=x²y²/(x-y)^4×[-y³(x-y)³]/x³=-y^5/[x(x-y)]=-y^5/(x²-xy)
=x^3-y^3-(x^3+y^3)=-2y^3^3表示三次方
xy-x-y+1=x(y-1)-y+1=x(y-1)-(y-1)=(y-1)(x-1)
x²y(x-y)-xy²(x-y)=xy(x-y)(x-y)=xy(x-y)²如果不懂,祝学习愉快!
(x+y)(x-y)-x(y+1)-y(y+1)=(x+y)(x-y)-(x+y)(y+1)=(x+y)(x-2y-1)
(x-1)(y-1)
Bxyy那么x为正数,因为负数a为任意有理数a^2等于0所以选B
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
利用公式法逆向因式分解(x+y)(x^2-xy+y^2)=x^3+y^3(x-y)(x^2+xy+y^3)=x^3-y^3都是公式可以自己乘开来试下可以抵消的（x^2-xy+y^2)和（x^2+xy+