Răspuns:
[tex]AA^{*}=(\det A)\cdot I_n[/tex]. Deci [tex]\det(AA^*)=\det A\det A^* = (\det A)^n[/tex], de aici rezulta ca [tex]\det A^*=(\det A)^{n-1}[/tex].
n=2020, deci [tex]\det A^* =(\det A)^{2019}[/tex].
Inlocuind, avem [tex] (\det A)^{2019}=2019^{673}[/tex], deci [tex]\det A=2019^{\frac{673}{2019}}=2019^{\frac{1}{3}}=\sqrt[3]{2019}[/tex].