x^2 xy-2y^2-x 7y-搜答案-神马作文网

x^2-xy-6y^2+3xy+y+2

3xy是3x原式=(x-3y)(x+2y)+3x+y+2十字相乘x-3y2×x+2y1所以原式=(x-3y+2)(x+2y+1)

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)^

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

(-3x^y+2xy)-(4x^+xy)=-3x^y+2xy-4x^-xy=-3x^y+xy-4x^所以填上-3x^y+xy-4x^

=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

（xy-y^2)÷x-y/xy=y(x-y)×[xy/(x-y)]=xy²

(x^-4y^)/(x^+2xy+y^)/(x+2y)/(2x^+2xy)=1.=3(a-b)/(10ab)*(25a^2b^3)/((a+b)(a-b))=15/2*(ab^2)/(a+

4X-2Y=16P4X+7Y=7P-9Y=9PY=-P3X+7P=35X=3.5P17.5P=35P=2

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

(x+y)(x-y)-x(y+1)-y(y+1)=(x+y)(x-y)-(x+y)(y+1)=(x+y)(x-2y-1)

xy+y平方+x-y-2=xy+x+y^2-y-2=x(y+1)+(y+1)(y-2)=(y+1)(x+y-2)

(x-y)/x²÷(x²-2xy+y²)/xy×(xy-x²)=(x-y)/x²÷(x+y)²/xy×x(y-x)=(x-y)²/

x^2y+4xy+4y

x^2y+4xy+4y=y(x²+4x+4)=y(x+2)²

原式=-x²y+2xy²+2x²y²-4xy³-3x³+27x³y-18x²y²+2x²y-18x&

x-y/xy-y^2计算

解(x-y)/(xy-y²)=(x-y)/y(x-y)=1/y

牛奶妹琪琪1：3x-5y=16①2x+7y=a-18②∵x,y互为相反数∴y=-x③把③代入①中,得3x-5×(-x)=163x+5x=168x=16x=2∴y=-2∴把x=2,y=-2代入②中,得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+