Using the hardware keys to remove password or reset the gesture lock. This tutorial will teach you how to remove password on your Galaxy A5 aka SM-A500 Andorid phone.

Turn off the phone completely.
Press and hold both Volume UP and HOME + power on the phone.
When Android Recovery menu screen appears release all keys.
Navigate and highlight "wipe data / factory reset" using the Volume down key and press power.
Navigate and highlight again to Yes -- delete all data and press power.
All data will be lost! Before doing a hard reset backup all important data.
After hard reset is done select Reboot system now. Press power to reboot the phone.