I would think you would use 1/3 of a cup but I am not sure.Hope it helps!
Answer: 
Step-by-step explanation:
Move all terms to one side.

Use the Quadratic Formula.
, 
Answer:
(Hope this helps can I pls have brainlist (crown)☺️)
Step-by-step explanation:
In pic
In order to keep the equation right, both sides have to balance each other. When you only perform an operation ( I'm assuming you're talking about division or multiplication) on one side, it messes up the balance because now one side is larger than the other.