已知|x-2|+|y+3|=0,求x、y的值 2.1-2+3-4+5-6+...+2007-2008+2009-2010+2011.3.若|x|=3,|y|=2,且xy＜0,求y分之x的值 4.已知|a-1|+（b+2）的平方=0,求(a+b)的2011此方的值 5.一根竹竿长约1.56米,那么它实际长度的范围是多

已知:3x-5y=0,求x/y,x-y/y,x-y/x 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|3x-y|+|x+y|=0,求x-y除以x*y的值. 已知|x|=2,|y|=3,|x+y|=-(x+y)求x-y 已知x+y=0,求x^3+x^2*y+xy^2+y^3 已知|2x-3y|+|3x-y-1|=0,求x,y的值. 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-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^2-3y^2=2xy(x>0,y>0),求代数式x+2y/x-y 已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)*(x-y)的值.