`x^5 - 4x^3 = 0`
`x^3(x^2-4)=0`
`=>` \(\left[ \begin{array}{l}x^3=0\\x^2-4=0\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=0\\x^2=4\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=0\\x^2=(±2)^2\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=0\\x^2=±2\end{array} \right.\)
Vậy `x=0` hoặc `x=±2`