Originally Posted by srikrishnak
See three exploits but all failed
You are on a custom ROM. Custom roms usually are rooted. So you shouldn't need to root.
Some custom roms have root access disabled by default and you can enable it by going into developer options.
Settings -> Developer options -> Root access. Select Apps and ADB.
If you do not see Developer options, enable it first.
Go to Settings -> About phone -> and tap on build number until you see the message that you are now a developer. (7-8 times)
You also clearly have a custom recovery if you are using a custom rom, so you can also flash SuperSu from recovery for example.