若x-y=5.xy=6,则x^2y xy^2=
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7.x*x+2*x+y*y-6y+10=(x+1)*(x+1)+(y-3)*(y-3)=0x+1=0且y-3=0所以x*y=-38.再加个4*x就好了11.原式=(x-2)*(x-2)+(y+3)*(
xy-6=2x+y≥2√(2xy)令a=√xy则a²-2√2a-6≥0所以a≤-√2,a≥3√2因为√xy>0所以√xy≥3√2xy≥12所以最小值是12
x=-1,y=-6或x=6,y=1代入式子得x^2-xy^2=37或30x^2y+xy^2=-42或42
“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
(x+y)^2=36x^2+y^2+2xy=36x^2+y^2=36-2*2.75=30.5(x-y)^2=x^2+y^2-2xy=30.5-2*2.75=25x-y=5或者-5已知x-y>0x-y=
∵根号xy≤(x+y)/2∴xy≤(x*2+y*2+2xy)/4当且仅当X=Y取等当x=y时原式可化为3x+6=x*2∴x*2的最小值为3/2
2x+y+6=xy化简得:Y=(2X+6)/(X-1)X不等于0因为正实数x.所以X>0所以X>1函数Y=(2X+6)/(X-1)是单调递增所以X=2为最小值,Y=10所以XY最小值为XY=20
第1小题:x²y-xy²=xy(x-y)=6(5)=30第2小题:(x+y)²=x²+y²+2xy=x²+y²-2xy+4xy=(
正实数x,y满足2x+y+6=xy∵2x+y≥2√2xy∴2√2xy+6≤xy∴xy-2√2xy-6≥0∴√xy≥3√2或√xy≤-√2﹙舍﹚∴xy≤18则xy的最小值是18.
因式分解,x^2-6xy+8y^2=(x-2y)(x-4y)=0所以x=2y或x=4y所以x/y=2或x/y=4
x-y=5(x-y)²=x²+y²-2xy=25由上两条可推出:x²+y²=37所以(x+y)²=x²+y²+2xy=3
xy/(x+y)=2(x+y)/xy=1/21/x+1/y=1/2(3x-xy+3y)/(-x+3xy-y)=(3/y-1+3/x)/(-1/y+3-1/x)=[3(1/x+1/y)-1]/[(3-(
(x+y)²=x²+2xy+y²=(x²-2xy+y²)+4xy=(x-y)²+4xy=49所以x+y=±7x²y+xy²
解x²y-xy²=xy(x-y)=5×1=5a²b+ab²=1∴ab(a+b)=1∵a+b=3∴3ab=1∴ab=1/3再问:a(a-b)-a+b=?再答:=a
是.20x=2y=10再问:看错了呵呵是xy的积再答:谢谢关注。xy的积等于20,是满足的。不知道你所表达的意思。
XY/(X+Y)=3,XY=3(X+Y)原式=[6(X+Y)+4XY]/[9(X+Y)+4XY]=[6(X+Y)+12(X+Y)]/[9(X+Y)+12(X+Y)]=[18(X+Y)]/[21(X+Y
x^2y+xy^2=xy×(x+y)=6×5=30
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-
由x,y为正得x=y/(y-1)>0、y=x/(x-1)>0,所以x>1、y>1,因此x+2y=y/(y-1)+2y=(y-1+1)/(y-1)+2(y-1+1)=3+1/(y-1)+2(y-1)>=