已知(x^2y^2)-4xy+5=4-x^2-y^2,则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+2)^2+|x+y+5|=0,求3x^2y-[2x^2y-(2xy-x^2y)-4x^2]-xy
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,则2x+3xy-2yx-2xy-y
已知X+Y=2XY,求4X-5XY+4Y 除以X+XY+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x²+y²-2x+4y+5=0,求X^4-y^4/2x^2+xy-y²·2x-y/xy
已知x^2+y^2-4x+6y+13=0求(xy+y^2/5x^2-5xy+xy+y^2)·(5/x+y)-(y/x-y
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=-1,则(3x-4y+2xy)-(2x-5y+5xy)=?
已知x-y=3,xy=5则代数式(3x-4y+5xy)-(2x-3y)+5xy的值是