multiple top and bottom by conjugate of 2-15i what will be 2+15i and will get
2 2(2+15i) 4 +30i 4 + 30i 4 +30i
------------ = -------------------- = -------------- = ------------- = ------------
2 - 15i (2-15i)(2+15i) 4 -(-225) 4 + 225 229
hope this will help you