Hello can someone please help me (with explanation ) how to do this

thank you.

If i have 20$ and i gave 5$ away how much i got

The roots of the function f(x) = x2 – 2x – 3 are shown. what is the missing number?

Ms.ortiz sells tomatoes wholesale. the function p(x)=-80x^2+320x-10, graphed below, indicates how much profit she makes on a load of tomatoes if she makes on a load of tomatoes if she sells them for 4-x dollars per kilogram. what should ms.ortiz charge per kilogram of tomatoes to make on a load of tomatoes?