长方形的周长是18,且满足-x的平方 2xy-y的平方 2x-2y-1=0

由x-y-x^2+2xy-y^2+2=0整理得(x-y+1)(x-y-2)=0∴x-y=-1或x-y=2∵长方形周长为16cm,它的长为x宽为y∴2(x+y)=16解方程组得x=3.5,y=4.5或x

周长是：18则x+y=9.（1）x平方-2xy+y平方-2x+2y+1=0(x-y）²-2（x-y）+1=0（x-y-1）²=0x-y=1.（2）联立（1）（2）解得：x=5,y=

周长16所以2(X+Y)=16X+Y=8(1)即(X-Y)²-4(X-Y)+4=0(X-Y-2)=0X-Y-2=0(2)所以X=5,Y=3.所以面积=XY=15

x^2(x^2+Y^2)+Y^2(x^2+Y^2)-6(x^2+Y^2)+9=0(x^2+Y^2)(x^2+Y^2-6)+9=0周长6,则X+Y=3,x^2+Y^2=9-2XY,直接带入就变成（9-2

(x-y)^2-2x+2y+1=0（x-y）²-2（x-y）+1=0（x-y-1）²=0x-y-1=0x-y=1由题可知x+y=14÷2=7则x=（7+1）÷2=4cmy=（7-1

题目是不是应该为x-y-x^2+2xy-y^2+2=0?周长为16,得x+y=8x-y-x^2+2xy-y^2+2=x-y-(x-y)^2+2(把x-y看成一个整体)=(2-x+y)(1+x+y)因为

x³+x²y-xy²-y³=x²(x+y)-y²(x+y)=(x²-y²)(x+y)=(x-y)(x+y)²=

由x2－y2－x＋y－14＝0得（x+y)(x-y)-(x-y)-14=0又由题意知x+y=16/2=8所以8(x-y)-(x-y)-14=07（x-y)-14=0x-y=2又因x+y=8解得x=5,

x-y-x^2+2xy-y^2+6=x-y-(x^2-2xy+y^2)+6=x-y-(x-y)^2+6=-[-(x-y)+(x-y)^2-6]=[(x-y)^2-(x-y)-6]=-[(x-y-3)(

一个长方形的周长为32,长为x,宽为y2*(x+y)=32,x+y=16,面积S=xyx^3+x^2y-xy^2-y^3=(x-y)(x+y)^2=0,x-y=0,x=y,x=y=4面积S=xy=16

先把它配成（X-Y)^2-2(X-Y)-8=0(X-Y+2)(X-Y-4)=0得到X-Y+2=0或者X-Y-4=0然后联立X+Y=8得到两个方程组,解出两组解,最后检验一下是否都符合题意满意的话望采纳

（x-y）²-3（x-y）-4=0①2（x+y）=16x+y=8②由①②得x=6cmy=2cm所以面积S=6*2=12平方厘米

2x-2y-x(平方)+2xy-y平方）+8=?这个计算式等号后数值是多少啊?现在按照等0计算,其他数值的计算方法可以参考.2x-2y-x(平方)+2xy-y(平方）+8=0==>2(x-y)-(x-

X+Y=8x^2-2y+y^2-x+y-2=0,x^2-y+y^2-x-2=0,(X+Y)^2-2XY-(X+Y)-2=064-2XY-8-2=0XY=27

x-y-﹙x-y﹚²﹢2＝0﹙x-y﹚²﹣﹙x-y﹚﹣2＝0﹙x-y-2﹚﹙x-y﹢1﹚＝0x-y-2＝0x-y=-1﹙不合题意﹚x-y=22﹙x﹢y﹚＝16x=5y=3面积=5×

即-(x-y)²+(x-y)+2=0(x-y)-(x-y)-2=0(x-y-2)(x-y+1)=0x-y>0所以x-y=2周长2(x+y)=16x+y=8所以x=5,y=3所以面积=xy=1

x(平方）-2xy+y（平方）-2x+2y-8=0(x-y)平方-2（x-y)-8=0(x-y-4)(x-y+2)=0因此x-y-4=0或x-y+2=0长方形的周长为16cm它的长为x宽为y,则x+y

设长是X厘米,宽是Y厘米.X+Y=84X-4Y-X^2+2XY-Y^2-4=0X=5Y=3面积是5×3=15（平方厘米）

2(x+y)=16x+y=8-------------(1)而(x-y)^2-2x+2y+1=0(x-y)^2-2(x-y)+1=0(x-y-1)^2=0x-y-1=0x-y=1-----------

x³+x²y-xy²-y³=0(x+y)²(x-y)=0又x+y>0故x-y=0即x=y又2(x+y)=284x=28x=7y=7面积=7*7=49再