\(x^2\left(x-3\right)+12-4x=0\)
\(\Rightarrow x^2\left(x-3\right)-4\left(x-3\right)=0\)
\(\Rightarrow\left(x^2-4\right)\left(x-3\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x^2-4=0\\x-3=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x^2=4\\x=3\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=3\\\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\end{matrix}\right.\)
\(\left(2x-1\right)^2-25=0\)
\(\Rightarrow\left(2x-1+5\right)\left(2x-1-5\right)=0\)
\(\Rightarrow\left(2x+4\right)\left(2x-6\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}2x+4=0\\2x-6=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}2x=-4\\2x=6\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=-2\\x=3\end{matrix}\right.\)
