a: \(x\left(x-1\right)-4x+4=0\)
=>\(x\left(x-1\right)-\left(4x-4\right)=0\)
=>\(x\left(x-1\right)-4\left(x-1\right)=0\)
=>\(\left(x-1\right)\left(x-4\right)=0\)
=>\(\left[{}\begin{matrix}x-1=0\\x-4=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=4\end{matrix}\right.\)
b: \(x^2\left(x-6\right)+24-4x=0\)
=>\(x^2\left(x-6\right)-\left(4x-24\right)=0\)
=>\(x^2\left(x-6\right)-4\left(x-6\right)=0\)
=>\(\left(x-6\right)\left(x^2-4\right)=0\)
=>\(\left(x-6\right)\left(x-2\right)\left(x+2\right)=0\)
=>\(\left[{}\begin{matrix}x-6=0\\x-2=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=6\\x=2\\x=-2\end{matrix}\right.\)
