` a) ` ` x^3 - 16x = 0 `
` => x(x^2 - 16) = 0 `
` => ` \(\left[ \begin{array}{l}x=0\\x^{2}-16=0\end{array} \right.\)
` => ` \(\left[ \begin{array}{l}x=0\\x^{2}=16\end{array} \right.\)
` => ` \(\left[ \begin{array}{l}x=0\\x=-4\\x=4\end{array} \right.\)
Vậy ` x = 0 ` hay ` x = -4 ` hoặc ` x = 4 `
` b) ` ` (x - 4)(x - 5)^2 = 0 `
` => ` \(\left[ \begin{array}{l}x-4=0\\(x-5)^{2}=0\end{array} \right.\)
` => ` \(\left[ \begin{array}{l}x=4\\x=5\end{array} \right.\)
Vậy ` x = 4 ` hoặc ` x = 5 `
