X Y=104......7,被除数最小是?-搜答案-神马作文网

主要考察合并同类项2x^2-7kxy+7xy+5y=2x^2+7*(1-k)xy+5y所以,如果想不含xy就必须要让xy前的系数7*(1-k)=0才行那么k=1

A-2B=5x²-3xy²+2xy-2(7xy²-2xy+x²y)=5x²-3xy²+2xy-14xy²+4xy-2x²

∵代数式xy-7y的公因式是y，∴xy-7y=y（x-7）．故答案为：y（x-7）．

∵x2-xy=7，2xy+y2=4，∴原式=（x2-xy）+（2xy+y2）=7+4=11，故答案为：11

xy'=y+xy的

xdy=(y+xy)dxdy/y=((1+x)/x)dxln|y|=ln|x|+x+cy=±e^(ln|x|+x+c)其中c是常数再问：真还不理解我们是选择题：y=cxe^xy=c+x-x^2y=cs

原式=6x+4xy+2xy+3x+2y-4xy+7y=9x+9y+2xy=9(x+y)+2xy=9×4+2×2=36+4=40

5xy+4x+7y+6x-3xy-4xy+3y=5xy-3xy-4xy+4x+6x+7y+3y=（5-3-4）xy+（4+6）x+（7+3）y=-2xy+10x+10y=-2xy+10（x+y）因为x

∵x2+xy=-3，xy+y2=7，∴（x2+xy）+（xy+y2）=-3+7=4，即x2+2xy+y2=4．

x^2y+xy^2=xy（x+y）=7x6=42再问：��(x+1)^2=13��x^2+2x+3=再答：x^2+2x+3=（x+1）^2+2=13+2=15

（4xy+12y)+[7x-(3xy+4y-x)]=4xy+12y+7x-3xy-4y+x=xy+8x+8y=xy+8(x+y)=(-2)+8*3=-2+24=22

先把代数式（5XY+4X+7Y)+(6X-3XY)-(4XY-3Y)化简（5XY+4X+7Y)+(6X-3XY)-(4XY-3Y)=5XY+4X+7Y+6X-3XY-4XY+3Y=-2XY+10X+1

(xx-xy)+(xy-yy)=xx-yy=7+4=11,

（7xy+4x-7y）+(6x-3xy)-(3y+4xy)=7xy+4x-7y+6x-3xy-3y-4xy=10x-10y=10（x-y）=10*3=30

a-2b=(5x²y-3xy²+4xy)-2(7xy²-2xy+x²y)=5x²y-3xy²+4xy-14xy²+4xy-2x&#

(5xy+4x+7y)+(6x-3xy)-(4xy-3y)=5xy+4x+7y+6x-3xy-4xy+3y=(5xy-3xy-4xy)+(4x+6x)+(7y+3y)=-2xy+10x+10y=-2x

7=xy-e^(xy),求dy/dx

如图.

∵A=8x²y-6xy²-3xy,B=7xy²-2xy+5x²y　∴C=3（A+B)　　=3(8x²y-6xy²-3xy+7xy²

已知A=5x^2y-3xy^2+4xy,B=7xy^2-2xy+x^2y.（1）求A-2B的值A-2B=5x^2y-3xy^2+4xy-2*(7xy^2-2xy+x^2y)=5x^2y-3xy^2+4

x²-7xy+12y²=0(x-3y)(x-4y)=0x1=3yx2=4yx=3y时原式＝9y²-3y²+y²/6y²=7/6x=4y时原式

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-