The absolute value function `f(x) = |x|` is a two pieces function, such that:

`f(x) = |x| = {(x, x >= 0),(-x, x < 0):}`

Graphing the absolute value function yields two lines, that are the bisectrices of the quadrants 1 and 2, such that:

You should notice that the values of the function `f(x) = |x|` are positive for `x in R` , hence, the domain of the function` f(x) = |x|` is the real numbers set `R` and the range is `[0,+oo).`