Virtualbox on Ubuntu 19.10

To install the official package and testing VirtualBox for your release, you need only

sudo apt install virtualbox

That will cause https://packages.ubuntu.com/eoan/virtualbox to be installed (note: it's found in 'multiverse' so that repository must be enabled; https://help.ubuntu.com/community/Repositories/Ubuntu)

You are trying to install a virtualbox packaged for bionic (18.04) which is unofficial for Ubuntu 19.10 (eoan). It needs to be removed (if installed) and the official 6.0.14 package installed from official repositories (for eoan).

nano /etc/apt/sources.list

write inside:

deb http://cz.archive.ubuntu.com/ubuntu disco main 

save with these shortcuts: Ctrl+O and Ctrl+X

next:

apt-get update
apt-get install libvpx5

As guiverc mention, you can do it in more simple way, just sudo apt install virtualbox

But for example, in my case, I had a vagrant, which specifically ask for `virtualbox-5.2'

Same you can do it like this: sudo apt install virtualbox-5.2, but for some cases it did not helped me. So I tried Josue Badbeat solution and it helped. Just add in source.list -> deb http://cz.archive.ubuntu.com/ubuntu disco main and then

apt-get update
apt-get install libvpx5