Ta có:
`x/2=y/3=z/4=x/2=y/3=(3z)/12=(x+y-3z)/(2+3-12)=14/(-7)=-2`
`x/2=-2=>x=-4`
`y/3=-2=>y=-6`
`z/4=-2->z=-8`
b,
`6x^5=24x^3`
`<=>6x^5-24x^3=0`
`<=>6x^3(x^2-4)=0`
`<=>6x^3(x-2)(x+2)=0`
`<=>`\(\left[ \begin{array}{l}6x^3=0\\x-2=0\\x+2=0\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=0\\x=2\\x=-2\end{array} \right.\)