已知(x+2)^2+|y-2/3|=0,求1/2x-2(x-1/3y^2)+(-3/2x+1/3y^2)的值.··囧·· 要对的啊···

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x-3y=0,求(2x+y)/(x^2-2xy+y^2)X(x-y) 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2x-3y=0则3x-y比x+2y= 已知x+y=0,求x^3+x^2*y+xy^2+y^3 已知4x-2y=0,求x-y/3x+2y的值 已知(x+y)^(2)+(x+3y-4)^(2)=0,求x,y的平方和 已知x=2y,求2x-y分之x-3y的值.0 已知|2x-3y|+|3x-y-1|=0,求x,y的值. 已知2x²-xy-3y²=0,求x-y/x+y 已知|x+y|+(x-y+3)^2=0,求x,y的值 已知x,y>0 2x+y+3=xy 求5x+4y最小值 已知x>0,Y>0,如何证x^2/y+y^2/x>=x+y 已知x-3y=0,求（2x+y)/(x^2-2xy+y^2)*(x-y)的值已知x-3y=0,求（2x+y)/(x^2-2xy+y^2)*(x-y)的值 已知|x|=2,|y|=3,|x+y|=-(x+y)求x-y 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值