Hi,
Different ways to eject a disc:
-File menu > Eject
-Hold down the Command key and press the e key
-Press Eject key on keyboard (on mine it’s the top/back right key)
-Hold down the trackpad “clicker” or hold the left click on a mouse while restarting/booting
-Applications > Utilities > open Terminal, then copy and paste or type in (exactly) the following:
drutil eject
-Hold down the command and s (or v) key while booting/restarting. Type in (exactly) the following:
/usr/bin/drutil eject
Type in the following to restart normally:
reboot
-If one of the above doesn’t work, make an appointment at an Apple Store “genius” bar and see if they can offer further help: https://support.apple.com/contact