I believe you might have started using Lightroom 6. You may go ahead and remove Lightroom 5 from your computer.
If you have not installed and used Lightroom 6 yet, I would suggest you to install Lightroom 6 and start using before you uninstall Lightroom 5 from your machine.
Yes I use Lightroom 6 with satisfaction
Sometimes I use app like Cleanmymac and I saw that I have Lightroom 5 in the Application folder that use over 1,2 gb in hd....
To delete Lightroom 5 I can simply drag the app to basket right ?
Yes, you can move Adobe Lightroom 5 folder from your application folder to the Trash.
Once done, please empty the trash to remove the application from your machine.