When graphing do you use an open or closed circle for >

Abby is preparing fruit punch for her party. she starts with a bowl filled with liquid that has 1/2 fruit juice and 1/2 sprite, but she decides it's too fruity. so she pours out 1/4 of the liquid, and then fills the bowl up again with sprite. what fraction of the punch is now sprite?

Hi i’m not sure how to do question 20 if u could explain how to do it that’d b great

Sole the equation 6n + 9 = -3n - 21 - 6 for n