(-2xy^2)^2×(-2x^2y)^3×(-x^2 z)÷(2x^3y^2)
化简(y-x)(z-x)/(x-2y+z)(x+y-2z)+(z-y)(x-y)/(xy-2z)(y+z-2x)+(x-
(2X+Z-Y)/(X^2-XY+XZ-YZ)-(Y-Z)/(X^2-XY-XZ+YZ)
实数x、y、z满足x=6-3yx+3y-2xy+2z
已知x>0,y>0,z>0,证明x^3/(x+y)+y^3/(y+z)+z^3/(z+x)≥(xy+xz+yz)/2
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
化简:x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y)
xy/x+y=1,yz/y+z=2,xz/x+z=3求x,y
已知3x-y+2z=x+2y+3z=0,求(3x^-xy+2y^)/(2x^+4xy+y^)值?
1.(x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2)
(y-x)/(x+z-2y)(x+y-2z)+(z-y)(x-y)/(x+y-2z)(y+z-2x)+(x-z)(y-z
证明 (x+y+z)^2>3(xy+yz+zx)
[x(x^2y^2-xy)-y(x^2-x^3y)]/3x^2y