a) 2x(x-3) - 3(x-3) =0
\(\Leftrightarrow\) (2x-3)(x-3)=0
\(\Leftrightarrow\) \(\left[{}\begin{matrix}2x-3=0\\x-3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=3\end{matrix}\right.\)
b)3x(x-4)* x +4 =0
\(\Leftrightarrow\) 3x2 -12x*x +4=0
\(\Leftrightarrow\)3x2-12x2 +4=0
\(\Leftrightarrow\) -9x2 + 22 =0
\(\Leftrightarrow\)22 - (3x)2 =0
\(\Leftrightarrow\)( 2-3x)(2+ 3x) =0
\(\Leftrightarrow\left[{}\begin{matrix}2-3x=0\\2+3x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=\dfrac{-2}{3}\end{matrix}\right.\)
c)4x2 - 1 = 0
\(\Leftrightarrow\)(2x)2 - 12= 0
\(\Leftrightarrow\)(2x -1)(2x +1)=0
\(\Leftrightarrow\left[{}\begin{matrix}2x-1=0\\2x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=\dfrac{-1}{2}\end{matrix}\right.\)
