Question

Use the properties of complex numbers to simplify (√−64+2i)+(10−√−9) .

Answer 1

Use i√a for square roots of negatives:
√(−64)=i√64=8i and √(−9)=i√9=3i.

So (√−64+2i)+(10−√−9) = (8i+2i)+(10−3i) = 10i + 10 − 3i = 10 + 7i.