已知3-x+2y=0,则2x-4y-3=( )
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为实数,根号3x+4 +y^2-6Y+9=0则x+y=?
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
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-2y/2x+3y=3/4,则x:y=
已知4x-2y=0,求x-y/3x+2y的值
已知x,y>0 2x+y+3=xy 求5x+4y最小值
已知x-y-3绝对值+(2x+2y+10)的平方=0,则(x+y)(x-Y)=
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)X(x-y)
已知{x-3y+2z=0 3x-3y-4z+0,则x:y:z=?