\(x\left(x-7\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x-7=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=7\end{matrix}\right.\)
\(x^2-7x=0\Rightarrow x\left(x-7\right)=0\Rightarrow\left[{}\begin{matrix}x=0\\x-7=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=0\\x=7\end{matrix}\right.\)