已知x-3y=0求2x-y x²-2xy y²
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根号下大于等于0所以x-2>=0,x>=22-x>,x
方程x2+y2-4x+1=0表示以点(2,0)为圆心,以3为半径的圆.设yx=k,即y=kx,由圆心(2,0)到y=kx的距离为半径时直线与圆相切,斜率取得最大、最小值,由|2k−0|k2+1=3,解
∵x2+y2-6x-8y+25=0,∴(x-3)2+(y-4)2=0,∴x=3,y=4,当x=3,y=4时,原式=43-34=712.
∵x+y=4,xy=3,∴原式=x2+y2xy=(x+y)2−2xyxy=16−63=103.
∵3x-5y=0,∴x=5y3,∴原式=5y3−2y5y3+3y=-111.
2x+yx2-2xy+y2•(x-y)=2x+y(x-y)2•(x-y)(2分)=2x+yx-y;(4分)当x-3y=0时,x=3y;(6分)原式=6y+y3y-y=7y2y=72.(8分)
x−yx÷(x−2xy−y2x)=x−yx÷(x2x−2xy−y2x)=x−yx÷x2−2xy+y2x=x−yx÷(x−y)2x=x−yx•x(x−y)2=1x−y,当x=2009,y=2010时,原
根据题意,x>0,y>0,则2yx>0,8xy>0,则2yx+8xy≥22yx•8xy=8,即2yx+8xy的最小值为8,若2yx+8xy>m2+2m恒成立,必有m2+2m<8恒成立,m2+2m<8⇔
原式=[(x+y)2(x-y)(x+y)+-4xy(x-y)(x+y)]×(x+3y)(x-3y)(x+3y)(x-y)=x-3yx+y,由已知得(3x-2y)(x+y)=0,因为x+y≠0,所以3x
∵实数x、y满足|2x-y+1|+2(3x-2y+4)2=0,∴2x−y+1=03x−2y+4=0,解得x=2y=5,原式=1-x−yx−2y×(x−2y)2(x+y)(x−y)=1-x−2yx+y=
x+2yx2−y2•(x+y)=x+2y(x+y)(x−y)•(x+y)=x+2yx−y;当2x+y=0时,y=-2x,原式=x−4xx+2x=−3x3x=-1.
要使根号3-x和根号x-3有意义则3-x=0x=3算出y=2yx次方:2³=8立方根为2最后结果为2
似乎题目应该是y=√(x-2)+√(2-x)+4x-2>=02-x>=0x=2代入得y=4yx=4*2=8y的x次=4²=16
因为y=3xy+x,所以x-y=-3xy,当x-y=-3xy时,2x+3xy−2yx−2xy−y=2(x−y)+3xy(x−y)−2xy=2(−3xy)+3xy−3xy−2xy=35.
∵x-y=4xy,∴2x+3xy-2yx-2xy-y=2(x-y)+3xyx-y-2xy=8xy+3xy4xy-2xy=112.故答案为:112.
x²y²-8xy+4x²+y²+4=0x²y²-4xy+4+4x²-4xy+y²=0(xy-2)²+(2x-y
由题意得,x−y=2x−2y+3=3,解得:x=4y=2,则可得a=3,b=2,b-a=-1,-1的立方根为:-1.
2x2-xy-3y2=0,(2x-3y)(x+y)=0,解得:2x-3y=0或x+y=0(分母为0,舍去),解得:x=3y2,则x−yx+y=3y2−y3y2+y=y5y=15.
你抄错题了吧X2+Y2+5/4=2X+Y移项,得(X-1)2+(Y-1/2)2=0X=1,Y=1/2