若x² |y-2|=0,求代数式x³-x²y xy² x²y-xy²-y³的值

∵(2x-y)²+|y+2|=0∴2x－y＝0y＋2＝0(非负数和为0,则每个非负数为0）∴x＝-1y＝-2∴[(x-y)²+(x+y)(x-y)]/2x＝[(-1＋2)²

绝对值只可能是正数或0正数之和不可能为0所以:X-2=0Y-1/3=0解得:X=2Y=1/33x+3y=3(x+y)=3(2+1/3)=7

x^2+y^2-2x+2y+2=0x²-2x+1+y²+2y+1=0∴(x-1)²+(y+1)²=0∴x-1=0y+1=0∴x=1y=-1∴x^2003+y^2

因为根号下2x-y+|y+2|=0所以2x-y=0.y+2=0解得x=-1.y=-2.代入式子=1.2题,设工业排水总量为x亿吨城镇排水总量为y亿吨.所以92%x+57%y=572*72%.x+y=5

:|x+二分之一|+(y-3)的平方=0∴x+1/2=0y-3=0∴x=-1/2y=3(3x+2y)的平方-2(x-y)(x+y)+3(x+y)(x-2y)=9x²+12xy+4y²

原式=（X²+Y²-X²+2XY-Y²+2XY-2Y²）/4Y=（4XY-2Y²）/4Y=（2X-Y）/2=0

绝对值大于等于0相加等于0则只有都等于0才成立所以X-2=0,Y+1/3=0X=2,Y=-1/32X+3Y=4-1=3

即y=2x所以原式=(x²-xy+y²)/(x²+xy+y²)=(x²-2x²+4x²)/(x²+2x²+4x

-3(2x-y)-{7x-[6x+2y-(10x-8y)]-x-2(3x-4y)}=-6x+3y-7x+(6x+2y-10x+8y)+x+6x-8y=-13x+3y-4x+10y+7x-8y=-10x

因为X-Y=1所以原式=x*1+y*（-1）+2013=x-y+2013=1+2013=2014

(x*x+y*y)(x*x+y*y)-4x*x*y*y=(x^4-2x^2y^2+y^4)=(x^2-y^2)^2=0x^2=y^2x/y=±1(x*x+5xy+y*y)/(x*x+2xy+y*y)=

X+Y分之X-Y等于3x=-2yX+Y分之2(x-y)减X+Y分之3X+Y=(-x-3y)/(x+y)=1

因为(x-y)/(x+y)=3,则(x＋y)/(x－y)＝1/3则5(x-y)(x+y)-(x+y)/2(x-y)＝5*3-1/(3*2)=15-1/6=89/6

/>x^2+2x+y^2-6y+10=0可化为(x+1)²+(y-3)²=0∴x=-1,y=3∴x²+y²-xy=1+9+3=13

（x+1）^2+(y-3)^2=0x=-1,y=32x-y=-5

|Y-2|+(X-1)平方=0而|Y-2|>=0;(X-1)平方>=0所以只能等于0,即y=2,x=1x立方-x平方y+xy平方+x平方y-xy平方-y立方=1-2+4+2-4-8=-7

题目应是：先化简,再求值：若（x-3）^2+|y+2|=0,求代数式3x^2y-[xy^2-2（2xy^2-3x^2y）+x^2y]+4xy^2的值．若（x-3）平方+|y+2|=0x-3=0y+2=

2X+3的绝对值+（x-3y+4)的平方=0由于绝对值和平方数都是大于等于零的.所以有:2x+3=0x-3y+4=0得:x=-3/2,y=5/6y-1=5/6-1=-1/6

x+y=1x-y=2(x+2y)(x-2y)-(2x-y)(-y-2x)=(x+2y)(x-2y)+(2x-y)(y+2x)=x²-4y²+4x²-y²=5x&

∵x^2-3y^2=2xy∴x^2-2xy-3y^2=0∴（x+y）（x-3y）=0∵x>0,y>0∴x-3y=0∴x=3y∴x+2y/x-y=3y+2y/3y-y=2y+2/3或=2/3(x+1)如