Bài 3:
a: \(6x^2-12x=0\)
\(\Leftrightarrow6x\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\end{matrix}\right.\)
b: \(4x^2-9-x\left(2x+3\right)=0\)
\(\Leftrightarrow\left(2x+3\right)\left(x-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{3}{2}\\x=3\end{matrix}\right.\)