4+5i.
Step 1: Remove the, unnecessary, parentheses.
(6+6i)-(2+i)
=6+6i-2-i
(the signs of the numbers in the second parentheses change because of the minus sign in front of it)
Step 2: Collect Like Terms.
=6-2+6i-i
Step 3: Subtract.
=4+5i.
(6+6i)-(2+i) = 4+5i.
