Laptop not showing screen but when it is connected to tv through hdmi cabel the screen is showing in tv not in laptop

[dhoomit.mangal29.fea]

Ubuntu software
Laptop taken from college
Laptop not showing the display but when it is connected to tv through hdmi cable it is showing display in tv not in laptop

 

[Saga Lout]

Does it have a Function key with an icon of two screens? If it has, use the Fn key and that Function key together to toggle back and forth between the built-in screen and the external.

 

[ShadowPrimeOne]

Open system preferences Click screen displays (under hardware) and then tick the check box for build in display