已知x+3y=0,则3y+2x/3y-2x的值为.

已知|x+y-3|+(x-y)2=0则 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知2x=3y,则y分之x=< >,y分之x+y=< >. 已知2x-3y=0则3x-y比x+2y= 已知3x-4y=0,则x^2-y^2/x^2+y^2 已知x^2-3xy+2y^2=0 则x/y+x/y= 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 已知3x =2y 求x/x+y+y/x-y-y²/x²-y² 已知x-y-3绝对值+(2x+2y+10)的平方=0,则(x+y)(x-Y)= 已知:3x-5y=0,求x/y,x-y/y,x-y/x 已知|x|=2,|y|=3,|x+y|=-(x+y)求x-y 已知x,y为实数,根号3x+4 +y^2-6Y+9=0则x+y=? 已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)X(x-y) 比例线段：已知x/y=2/3,则 x/x+y= ,x-y/x+y= 要过程! 已知方程组{(X+Y)-3(X-Y)=7,2(X+Y)+(X-Y）=-7}则(X+Y)(X-Y)= 已知-4x+3y-13+(y-3)^2=0,则x·y= 已知|x-y+4|+(y-3)的二次幂=0,则2x+y=? 已知Ix+y+1I+(x-y+3)^2=0,则(x+y)^2004等于