Algebraic Geometry/Functions

A function is a relation mapping one set (the domain) to another (the codomain) such that every element in domain has a unique image in its co-domain.

Examples of functions would include $$2x+3y=9$$, $$4x+7z=8$$

function is denoted by symbol $$f(x)$$ or $$g(x)$$ where $$x$$ is the independent variable and function are written as $$f(x)=7x+9$$