已知（2x-5y-20)²+|2x-3y-4|=0求x,y的值

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.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 已知x² +y²+5/4=2x+y,求y-x的值 已知4x-2y=0,求x-y/3x+2y的值 已知x^3+xy^2+x+x^2y+y^3+y=0,求5x-6y/3x+4y的值. 已知y-2x=0,求3x²-2y²/(x+y)(x-y)的值 已知|3x+2y-4|+4(5x+7y-3)²=0,求x,y的值. 已知 (2x+3y-4)²+|x+3y+1|=0 求3x+5y的值 1.已知:x-2y=3,求[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]除4x 的值 已知x-2y=2011,求[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]÷4x的值. 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y/2x-y的值