\(\left(x+16\right)\left(x+56\right)=160\)
\(\Leftrightarrow x^2+56x+16x+896=160\)
\(\Leftrightarrow x^2+72x+896=160\)
\(\Leftrightarrow x^2+72x+1296-400=160\)
\(\Leftrightarrow\left(x+36\right)^2=560\)
\(\Leftrightarrow\orbr{\begin{cases}x+36=\sqrt{560}\\x+36=-\sqrt{560}\end{cases}}\Rightarrow\orbr{\begin{cases}x=4\sqrt{35}-36\\x=-4\sqrt{35}-36\end{cases}}\)