\(\left(x^2+5x\right):x=0\)
\(\Rightarrow x^2+5x=0\)
\(\Rightarrow x\left(x+5\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x+5=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=-5\end{matrix}\right.\)
\(\left(x^2+5x\right):x=0\)
\(\Leftrightarrow\dfrac{x^2+5x}{x}=0\)
\(\Leftrightarrow\dfrac{x\left(x+5\right)}{x}=0\)
\(\Rightarrow x+5=0\Leftrightarrow x=-5\)