Write a function that describes a relationship between two quantities. From a context, determine an explicit expression, a recursive process, or steps for calculation. Combine standard function types using arithmetic operations (e.g., given that π(π₯) and π(π₯) are functions developed from a context, find (π + π)(π₯), (π β π)(π₯), (ππ)(π₯), (π/π)(π₯), and any combination thereof, given π(π₯) β 0). Compose functions.