当x=-3/5,y=2/3时,求式子[(2x/2x+y)-(4X^2/4x^2+4xy+y^2）]/[（2x/4x^2-

已知（x+2）^2+|x+y+5|=0,求3x^2y-[2x^2y-(2xy-x^2y)-4x^2]-xy 已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)} 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 已知x,y>0 2x+y+3=xy 求5x+4y最小值 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y* 已知(x+2)^2+|x+y+5|=0,求3x^2y+{-2X^2y-[-2xy+(x^2y-4x^2)]-xy} 已知2x-y=10,求式子[(x^2+y^2)-(x-y)^2+2y(x-y)]/4y (4xy-2y²)/4 当|x+5|+(y-2)²=0时,求式子(4x-2y²)-[5x-（x-y²）]-x的值. 当x-y=1时,求x^4-xy^3-x^3y-3x^2y+3xy^2+y^4的值 当x=-4 y=-2时 求代数式-3x平方y+3xy平方+x?+3x平方y-3xy平方-y, 已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² 当x=2007,y=2008时,求x^4-y^4/x^2-2xy-y^2÷x^2+y^2/y-x=