Install and Upgrade firefox in Ubuntu 10.10

[1] http://tips4linux.com/install-firefox-40-in-ubuntu-1010-via-apt/      ----via APT command line
[2] http://blog.sudobits.com/2011/03/23/firefox-4-for-ubuntu-10-10/  ----via GUI

sudo add-apt-repository ppa:mozillateam/firefox-stable && sudo apt-get update && sudo apt-get install firefox