b) \(2020^{x\left(x+6\right)}=1\)
\(\Leftrightarrow2020^{x\left(x+6\right)}=2020^0\)
\(\Leftrightarrow x\left(x+6\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x+6=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=0\\x=-6\end{cases}}\)
Vậy \(x=0\)hoặc \(x=-6\)