36(x+2y)^2-25(x-2y)^2=?x^8-1=?(x-y+z)^2-(2x-3y+4z)^2=?

试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai x+2y=3 x+y+z=36 2x+y+z=15 2y=3z x-y=1 x+2y+z x-z=-1 2x+z-y=1 x/2=y/3=z/5 x+3y-z/x-3y+z 36(x+2y)^2-25(x-2y)^2=?x^8-1=?(x-y+z)^2-(2x-3y+4z)^2=? 已知 x,y,z都是正实数,且 x+y+z=xyz 证明 (y+x)/z+(y+z)/x+(z+x)/y≥2(1/x+1 x,y,z为实数 且(y-z)^2+(x-y)^2+(z-x)^2=(y+z-2x)^2+(x+z-2y)^2+(x+y x,y,z为实数且(y-z)平方+(x-y)平方+(z-x)平方=(y+z-2x)平方+(z+x-2y)平方+(x+y- (x+y-z)^2-(x-y+z)^2=? 已知x/2=y/3=z/4,求下列各式 （1）(x+y+z)/x (2)(x-y+2x/(x-y-2z) 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,