Run in terminal following commands:
wget -O- http://deb.opera.com/archive.key | sudo apt-key add - deb http://deb.opera.com/opera/ stable non-free sudo apt-get update sudo apt-get install opera
Run in terminal following commands:
wget -O- http://deb.opera.com/archive.key | sudo apt-key add - deb http://deb.opera.com/opera/ stable non-free sudo apt-get update sudo apt-get install opera