计算(x+2y-3z)^2+(x-2y+3z)(x+2y-3z)
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
x/2=y/3=z/5 x+3y-z/x-3y+z
计算:3x-2y- [-4x+(z+3y)]
1.(x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2)
计算(x+2y-3z)的平方+(x-2y+3z)(x+2y-3z)
(x+2y+3z)-(3x+2y-z)+(2x-3y+4z) 用直式计算
因式分解:25x y^2 z^2 (x+y-z)-30xyz(z-x-y)^2+5x y z^3 (z-x-y)
已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3
x=y/z=z/3,x+y+z =12,求2x+3y+4z是多少,
(y-x)/(x+z-2y)(x+y-2z)+(z-y)(x-y)/(x+y-2z)(y+z-2x)+(x-z)(y-z
如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y,
运用乘法公式计算:(x+2y-3z)(x-2y+3z)