(-3-3i)(-1-3i)
Use the FOIL method:
First, multiply the first terms: -3*-1.
Second, multiply the outside terms: -3*-3i.
Third, multiply the inside terms: -3i*-1.
Last, multiply the last terms: -3i*-3i.
Add all the results together and collect like terms. Remember i2 = -1.