STEPS
1. Power Off Your Tab
2. Hold Volume Buttons(+-) and power button. Release power button when tab vibrate
3. When Download mode appear press Volume Down Recovery will Prompt
4. Select Wipe Data/Factory Reset
5. Enter password and confirm Yes to delete all user data
TRICK
When Ask for password the password should be 4 digit long.
Use The Second-4Th Last-3rd Last-2nd Last Digit From Imei For Password
Done