Question 37747
When adding and subtracting radical expressions we first need to combine like terms. 
Remember, to add like terms the radicals must have the same base and the same index.
So...
{{{ sqrt(11) - 5sqrt(2) + 6sqrt(11) - sqrt(2) }}}
Becomes...
{{{ sqrt(11)+ 6sqrt(11) - 5sqrt(2) - sqrt(2) }}}
And...
{{{ 7sqrt(11) - 7sqrt(2) }}}
Since these expressions do not cantain the same base and the same index, they cannot be simplified ant further.
I hope this helps.
Good Luck!