\(3x.\left(\left|x\right|-4\right)\left(x^4-81\right)=0\)
\(\Rightarrow\hept{\begin{cases}3x=0\\\left|x-4\right|=0\\x^4-81=0\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}3x=0\\x-4=0\\x^4=81\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x=0\\x=4\\x=-3;3\end{cases}}\)
Vậy x có 4 giá trị