What is the formula for slope-intercept form of the line

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?

F(x)=x/2-2 and g(x)=2x^2+x-3 find (f+g)(x)

Need on this geometry question. explain how you did it.