x+Y-21+(2x+3y-5)^2=0 求x.y的值 尽快

若x-y/x+y=5,求x-y/2x+2y+5x+5y/3x-3y的值 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.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-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知x^3+xy^2+x+x^2y+y^3+y=0,求5x-6y/3x+4y的值. 已知x-3y=0(y≠0)求2x+5y/3x-2y的值 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-3y=0,求(2x+y)(x-y)/x^2-2xy+y^2的值 若x^5+x^4y+x^4+x+y+1=0,且3x+2y=1,求x,y的值 |x+y+2|+(2x+3y+5)²＝0 求x y的值. 已知x-3y=0,求2x+y/x-2xy+y乘(x-y)的值