已知x>0,Y>0,如何证x^2/y+y^2/x>=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*x+4x+y*y-2y+5=0,则x*x+y*y=?
已知x,y满足约束条件:x-y+1>=0,x+y-2>=0,x
已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)X(x-y)
已知x-y/x=x/x-2y(y不等于0),求x:y的值
已知x-y/x=x/x-2y(y不等于0),求x: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^2+4y^2-4x+4y+5=0,求(y^4-x^4)/(y-2x)(x+y)*2x-y
已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
已知x.x+y.y+8x+6y+25=0,求代数式(x.x-4y.y)/(x.x+4xy+4y.y)-x/(x+2y)的