1. Using tables; 2. Using graphs; 3. Defining by a formula; 4. Describing with words.
Work Step by Step
1. A function may be defined by tabularly representing the argument $x$ and the value of the function $f(x)$ 2. A function may be given by the curve in the $xy$ plane where coordinates of every point from the curve represent respectively, the argument and the value of the function: $P(x,f(x)).$ 3. A function may be defined by a fomula i.e. $f(x)=ax^2+bx+c$. 4. A function may be described with words. For example, you can say, the price function is defined as: Its argument is a product. Its value is the price of that product.