无法安装Cisco Packet Tracer 8.2.2：依赖libgl1-mesa-glx无法安装问题求助

各位好，我最近在电脑上装Cisco Packet Tracer 8.2.2的时候彻底卡壳了，试了好几种办法都搞不定。当我运行Cisco提供的CiscoPacketTracer822_amd64_signed.deb安装包时，终端直接抛出了一堆错误：

Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Note, selecting 'packettracer' instead of './CiscoPacketTracer822_amd64_signed.deb'
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 packettracer : Depends: libgl1-mesa-glx but it is not installable
E: Unable to correct problems, you have held broken packages.

我寻思先把缺失的依赖补上总没错吧？结果尝试安装libgl1-mesa-glx的时候，又踩了个坑，错误提示是：

Package libgl1-mesa-glx is not available, but is referred to by another package.
This may mean that the package is missing, has been ob...

（原错误内容没粘贴完，我只把能看到的部分放上来了）

有没有大佬能帮我捋捋这事儿该怎么解决呀？

备注：内容来源于stack exchange，提问作者Aiden Rees