x²-xy-3x=0
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2y+3x=2xy(2y+3x)/(2xy)=1(1/x)+(3/y)=11≥2√(3/(xy))1≥12/(xy)xy≥12xy的最小值是12
3x*+xy-2y*=0(3x-2y)(x+y)=0那么x=2y/3或x=-yy/x=3/2或x/y=-1(x/y)-(y/x)-(x*+y*)/(xy)=(x/y)-(y/x)-(x/y+y/x)=
绝对值大于等于0,相加等于0,若有一个大于0,则另一个小于0,不成立所以两个都等于0所以x+y+1=0xy+3=0xy=-3x+y=-1两边平方x^2+2xy+y^2=(-1)^2x^2+y^2=1-
由y=3xy+x得x-y=-3xy2x+5xy-2y/x-2xy-y=2(x-y)+5xy/x-y-2xy=-6xy+5xy/-3xy-2xy1/5
y-x-2xy=0y-x=2xyx-y=-2xy(3x+xy-3y)/(y-xy-x)=[3(x-y)+xy]/[(y-x)-xy]=(-6xy+xy)/(2xy-xy)=-5xy/xy=-5
答:x>0,y>0x-√(xy)-2y=0(√x-2√y)(√x+√y)=0因为:x>0,y>0所以:√x+√y>0所以:√x-2√y=0所以:√x=2√y所以:x=4y所以:[x+3√(xy)+2y
(-3x^y+2xy)-(4x^+xy)=-3x^y+2xy-4x^-xy=-3x^y+xy-4x^所以填上-3x^y+xy-4x^
解(x+1)平方+/y-1/=0∴x+1=0,y-1=0∴x=-1,y=1∴2(xy-5xy平方)-(3xy平方-xy)=(2xy+xy)+(-10xy平方-3xy平方)=3xy-13xy平方=3×(
1、x-2√xy-3y=(√x-3√y)(√x+√y)=0解得√x=3√y或者√x=-√y(舍去)也就是x=9y2x+y+√xy除以y-x-√xy=(2*9y+y+3√y*√y)/(y-9y-3√y*
3x²+3xy=03x²=-3xy因为x不等于0所以x=-y所以x:y=1:-1
y-x-2xy=0所以x-y=-2xyy-x=2xy所以原式=[3(x-y)+xy]\[(y-x)-xy]=[3×(-2xy)+xy]\(2xy-xy)=-5xy\xy=-5
x²-10x+25+|y-3|=0(x-5)²+|y-3|=0所以x=5,y=3代入计算即可
(3x^2+2xy)/xy-(2x^2-xy)/xy=(3x^2+2xy-2x^2+xy)/xy=(x^2+3xy)/xy=x(x+3y)/xy=(x+3y)/y
x^2+2xy-3y^2=0x^2+2xy+y^2-4y^2=0(x+y)^2=4y^2x+y=2y或x+y=-2yx=y或x=-3y因为两个正实数所以x=yx^2+xy+y^2/x^2-xy+y^2
①xy同非负时,2x-3√xy-2y=(2√x+√y)(√x-2√y)=0∴√x=2√y,x=4y②xy同负时,2x-3√xy-2y=[2√(-x)+√(-y)][√(-x)-2√(-y)]=0∴√(
x+y=5xy(2x-3xy+2y)/(x+2xy+y)=[2(x+y)-3xy]/[(x+y)+2xy]=(2×5xy-3xy)/(5xy+2xy)=7xy/7xy=1再问:若x+1/x=3,求(x
2x-3√(xy)-2y=0(2√x+√y)(√x-2√y)=0因为x>0,xy≥0所以y≥02√x+√y>0所以√x-2√y=0,即x=4y(x^2+4xy-16y^2)/(x^2+xy-9y^2)
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-
∵x-y=4xy∴原式=[2(x-y)+3xy]/[-(x-y)-2xy]=(8xy+3xy)/(-4xy-2xy)=11xy/(-6xy)=-11/6