I have also one doubt: why did you not simply look into Oracle documentation for correct syntax of UPDATE statement?
SQL statements are fully described in SQL Language Reference book, which is available with other Oracle documentation e.g. online on http://tahiti.oracle.com/
For 11gR2, it is placed here: http://docs.oracle.com/cd/E11882_01/...8.htm#i2067715
Second example shows what you want (change values of multiple columns).
Next time, please, search yourself!