(3x-2y)(9x²+6xy+4y²)

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)

x^+2xy+y^+4=16(x+y)²=16-4=12(1)x^-2xy+y^=16(x-y)²=16(2)(1)-(2)2y*2x=-4xy=-1(3xy+6y^)+|x^-(

x＾2-3xy／x＾2－6xy+9y＾2=x(x-3y)/(x-3y)^2=x/(x-3y)

Solution:x^2-2xy+3y^2=9(1)4x^2-5xy+6y^2=30(2)Eq(1)*5-Eq(2)*2,wehavex^2-y^2=5(3)Eq(2)-Eq(1),wegetx^2+

1、平方差原式=[(2x+3y)+(x+2y)][(2x+3y)-(x+2y)]=(2x+3y+x+2y)(2x+3y-x-2y)=(3x+5y)(x+y)2、3|x-3|+(x-3y)²=

x^2-6xy+9y^2+x^2y-9y^3=(x-3y)^2+y(x^2-9y^2)=(x-3y)^2+y(x+3y)(x-3y)=(x-3y)(x-3y+xy+3y^2)

方是什么是平方吗再问：嗯再答：=x(2x-3)-3y(2x-3)=(2x-3)(x-3y)

√x^-2xy+y^2+x^2-6xy+9y^2/x-3y=√(x-y)^2+(x-3y)^2/x-3y由于y>x=y-x+x-3y=-2y=-2√5

（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y=（x+y)（x-y)-y^2+（x-y)^2-2y（3x^2-xy)÷2y=（x+y)（x-y)-y^2+（x-y)^2

急不解决问题最后还是靠自己多动脑看课本其实都是课本上的再问：你看看啊！课本上没有，不会才问的！.........

[3xy(1-x)-6xy(x-1/2)]*2x*(-xy)平方=(3xy-3x²y-6x²y+3xy)(2x³y²)=12x^4y³-18x^5y&

xy/x+y=6∴xy=6(x+y)3x-2xy+3y/-x+3xy-y=[3x-12(x+y)+3y]/[-x+18(x+y)-y]=-9(x+y)/17(x+y)=-9/17再问：你在啊？再答：在

[(x-y)/(x+3y)]/[(x^2-y^2)/(x^2+6xy+9y^2)]-xy/(x+y)=(x-y)/(x+3y)*(x+3y)^2/(x-y)(x+y)-xy/(x+y)=(x+3y)/

原式=(x-y)/(x+3y)×[(x+3y)^2/(x+y)(x-y)]-2y/(x+y)=(x+3y)/(x+y)-2y/(x+y)=(x+3y-2y)/(x+y)=(x+y)/(x+y)=1

第一项与第三项先合并9xy(x-y)(x+1)-3y(x-y)(3x+2y)+6y^2*(x-y)(x+1)=(x-y)(x+1)(9xy+6y^2)-3y(x-y)(3x+2y)=(x-y)(x+1

1、(-7x^y)(2x^y-3xy^3+xy)=-14x^(2y)+21x^(y+1)y^3-7x^(y+1)y;2、((x-y)^6)/((y-x)^3)/(x-y)=-(x-y)^3/(x-y)

x²-xy+3y-3x=x(x-y)-3(x-y)=(x-y)(x-3)2x²+xy-y²-4x+5y-6=(2x-y)(x+y)-4x+5y-6=(2x-y+2)(x+

不会

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

因为,x-y=3xy所以：-3x+6xy+3y/[(7x-5y)-9xy-(3x-y)]=[-3(x-y)+6xy]/[(7x-5y)-9xy-(3x-y)]=[-3*3xy+6xy]/[7x-5y-