已知x-y=-2/3 求(x^2+y^2)^2-4xy(x^2+y^2)+4x^2y^2

已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 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/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² 已知x,y>0 2x+y+3=xy 求5x+4y最小值 已知x-y=4xy,求x-2xy-y分之2x+3xy-2y的值! 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y 已知x-y=3,xy=1,求（-2x+2x+3y)-(3xy+2y-2x)-(x+4y+xy) 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=1,xy=-2.求：(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 .已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 已知3x*+xy-2y*=0,求(x/y)-(y/x)-(x*+y*)/(xy)的值.*是平方