Test if MySQL is running: as root, type in the shell service mysql status. This should inform you whether apache is running ro not. If it's not running, you can start it with service mysql start. Note that after mysql installation it will be probably configured to start automatically when your computer boots up. If it's not, you should change it.
As a final test, type
mysql at the prompt. This should bring you to an interactive prompt. You can exit with
Welcome to the MySQL monitor. Commands end with
Your MySQL connection id is 29 to server version: 3.23.52
Type 'help;' or '
\h' for help. Type '
\c' to clear the buffer.