3y的平方-2y-2=0

已知2x的平方-xy-3y的平方=0,(2x-3y)(x+y)=0;2x-3y=0或x+y=0;y=2x/3或y=-x（舍去）;求(x-y)/(x+y)的值=(x-2x/3)/(x+2x/3)=1/3

3x^2+xy-2y^2=(3x-2y)(x+y)=0x=-2y/3,或x=-y但由于你要求的式子中分母里有X平方-Y平方x=-y舍去其他就代入吧

答：x+y+z=3y=2zy≠0,则z≠0所以：y=2z/3x+2z/3+z=2zx=z/3令z=3k,y=2k,x=k(xy+yz+zx)/(x²+y²+z²)=(2k

:|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

楼主是不是把题写错了呀,应该是（X+2)^2+/Y+1/=0吧因为（X+2)^2大于等于0/Y+1/大于等于0所以只有同时为0时,和才为0即X=-2Y=-1带入原式=4

（x+y）(x+2y)=x²+xy+2xy+2y²=x²+3xy+2y²

y的三次方-3y平方+y-2=y（y的平方-y-1）-2（y的平方-y-1）-4=-4

x²-4x+y²-10y+29=0x²-4x+4+y²-10y+25=0（x-2）²+（y-5）²=0∵（x-2）²≥0,（y-5

∵|2x-y+5|+(x+2y-4)的平方=0∴2x-y+5=0,x+2y-4=0∴2x-y=-5,x+2y=4x-3y=-9则（2x-y)的三次方-（x-3y)(y-2x)的平方=(-5)^3-(y

x平方-3xy+2y平方=0(x-2y)(x-y)=0x=2yx=y(1)x=2y则xy分之x平方+y平方的值=((2y)^2+y^2)/(2y*y)=(4y^2+y^2)/(2y^2)=5/2(1)

x平方+xy-2y的平方=0,(x-y)(x+2y)=0x-y=0或x+2y=0x=y或x=-2yx/y-y/x-x的平方+y的平方/xy=(x²-y²-x²-y

这题简单的啊(X-Y)(X-Y)-(X-Y)=3解下就可以了解之得:X-Y=1/2+根号13/2或者1/2-根号13/2

(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)/(2y)=X^2-y^2-y^2+X^2+y^2-2xy-3x^2+xy=-x^2-y^2-xy=-(x^2+y^2+xy-3

上题整理得：(X-Y)-(X-Y)平方+2=0得（X-Y)平方-（X-Y)-2=0（X-Y-2)(X-Y+1)=0得到X-Y=2或者-1

是2x吧x的平方-2x+y的平方-6y+10=0,x²-2x+1+y²-6y+9=0(x-1)²+(y-3)²=0x-1=0,y-3=0x=1,y=3再问：应该

x^2-y^2-x+3y-2=(x^2-x+1/4)-(y^2-3y+9/4)=(x-1/2)^2-(y-3/2)^2=(x-1/2-y+3/2)(x-1/2+y-3/2)=(x-y+1)(x+y-2

x^2+y^2-2x-4y+5=0(x^2-2x+1)+(y^2-4y+4)=0(x-1)^2+(y-2)^2=0∴(x-1)^2＝0(y-2)^2＝0∴x-1=0x=1∴y-2=0y=2所以x=1,

先由两已知方程解得x=27/8,y=9/8,然后接下来的自己算啦...两方程的话,先将第二个两边都乘三,再于第一个相减得出y,再将y带进方程得x

(x+2)^2-(y-3)^2=(x+y)*(x-y)x^2+4x+4-y^2+6y-9=x^2-y^24x+6y-5=0即为所求的方程

由x-2y=0得x=2y,x²=4y²,当x,y都不为0时,(2x²-3y²)/(x²+5y²)=(8y²-3y²)/(