Đáp án + Giải thích các bước giải:
`a)`
`3x^{3}-12x=0`
`<=>3x(x^{2}-4)=0`
`<=>3x(x-2)(x+2)=0`
`<=>` \(\left[ \begin{array}{l}x=0\\x-2=0\\x+2=0\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x=0\\x=2\\x=-2\end{array} \right.\)
`b)`
`3x(5x-2)-12(2-5x)=0`
`<=>3x(5x-2)+12(5x-2)=0`
`<=>(5x-2)(3x+12)=0`
`<=>` \(\left[ \begin{array}{l}5x-2=0\\3x+12=0\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x=\dfrac{2}{5}\\x=-4\end{array} \right.\)
