已知x y=6,xy=4,则x²y xy²的值是-搜答案-搜搜考试网

x+y=3,xy=14x+3xy+4y=4(x+y)+3xy=4x3+3x1=12+3=15祝学习进步,望采纳,不懂的欢迎追问.再问：怎么又是你啊。。。再问一道题：代数式x²＋x＋3的值为7

由,X/3+Y/4=1得y=4-4x/3.故求xy的最大值即求：xy=x(4-4x/3)=4x-4/3*x^2的最大值.根据抛物线性质易求得最大值即为顶点处.

因为x/y=2所以x=2y是[x^2-xy+3y^2]/[x^2+xy+6y^2]吧=(4y^2-2y^2+3y^2)/(4y^2+2y^2+6y^2)=5y^2/12y^2=5/12

原式=3xy+6y-xy+6x=2xy+6(x+y)=2*(-2)+6*4=24-4=20

因为x-y=4xy所以x-2xy-y=2xy2x+3xy-2y=11xyx-2xy-y分之2x+3xy-2y=5.5

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+y2+3xy=（x+y）2+xy，∵x+y=4，xy=2，∴x2+y2+3xy=42+2=18．故答案为18．

原式=[4(x+y)-2xy]分之[(x+y)+xy]=[4(3xy)-2xy]分之[(3xy)+xy]=10xy分之2xy=5分之1

“x愚人国度”您好,很高兴为您解答!x^2y+xy^2=xy(x+y)=-3*6=-18

x^2y+xy^2=xy(x+y)=-3*6=-18

3（xy+2y）-（xy-6x）=3xy+6y-xy+6x=2xy+6(x+y)=2×(-2)+6×4=-4+24=20

x+根号xy-6y=0(根号x-2根号y)(根号x+3根号y)=0解得根号x=2根号y即x=4y或根号y+3根号y=0不成立所以4x+5根号xy-6y分之x+2根号xy=[4y+2根号(4y*y)]/

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

∵x-y=4xy，∴2x+3xy-2yx-2xy-y=2(x-y)+3xyx-y-2xy=8xy+3xy4xy-2xy=112．故答案为：112．

xy+1/xy>=2√（xy*1/xy）=2(当xy=1/xy即xy=1时取等号)x/y+y/x>=2√（x/y*y/x）=2(当x/y=y/x即x=y取等号)当x=y=1时可以同时满足两项的等号要求

因为xy/（x+y）=1/2所以x+y=2xy原式=3（x+y)-5xy/(-x-y+3xy)=3*2xy-5xy/(-2xy+3xy)=xy/xy=1

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

x²y+xy²=xy(x+y)=4×6=24

已知x+xy=-2,xy-y=-6则X+Y=42x｛-4y-3[（x+xy）²+x]-½[（y-xy）²-2y]=2x｛-4y-3[（-2）²+x]-&fr

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-