Can someone answer these questions and explain the reasoning?

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?

Find the domain of the following expression: 1/(√x)-2

The function models the number of accidents per 50 million miles driven as a function