已知2x-y=1/4,xy=-2,求2x^5y^4-x^4y^5

已知x,y>0 2x+y+3=xy 求5x+4y最小值 已知X+Y=2XY,求4X-5XY+4Y 除以X+XY+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x²+y²-2x+4y+5=0,求X^4-y^4/2x^2+xy-y²·2x-y/xy 已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² 已知（x+2）^2+|x+y+5|=0,求3x^2y-[2x^2y-(2xy-x^2y)-4x^2]-xy 已知(x+2)^2+|x+y+5|=0,求3x^2y+{-2X^2y-[-2xy+(x^2y-4x^2)]-xy} 已知x+y=5,xy=2,求5x+4y-3y-2y+xy的值 已知x+y=5,xy=2,求5x+4y-3x-2y+xy的值 已知x2+y2-2x+4y+5=0,求(x^4-y^4)/(2x^2+xy-y^2)·[(2x-y)/(xy-y^2)] 已知2x-y=1/4,xy=-2,求2x^5y^4-x^4y^5 已知5x^2-4xy+y^2+y-2x+1=0,求（x-y）^2005