A=y(x-y)(x-z)+z(x-y)(z-x) 问：（1）将多项式A分解因式（2） x/2=y/3=z/4,求A/（

A=y(x-y)(x-z)+z(x-y)(z-x) =y(x-y)(x-z)-z(x-y)(x-z)
= (x-y)(x-z)(y-z)
x/2=y/3=z/4=t
x=2t,y=3t,z=4t

代入
A/（xyz）=-2t*t*t/2*3*4*t^3=-1/12