\(x^2+4x-5=0\)
\(\Leftrightarrow x^2+5x-x-5=0\)
\(\Leftrightarrow x^2+5x-\left(x+5\right)=0\)
\(\Leftrightarrow x\left(x+5\right)-\left(x+5\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+5\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-1=0\\x+5=0\end{cases}\Rightarrow\orbr{\begin{cases}x=1\\x=-5\end{cases}}}\)