f(x) = |x|
Since the variable x is given with absolute value signs, the function f(x) will always take on positive values for all values (negative or positive) of x.
To solution of a function is the value of the function such that f(x) = 0. The function f(x) = 0 when x = 0 because at every value of x on the graph, y = the same value.
e.g. when x =1, y=1. When x =2, y=2 etc...
This is the graph of f(x) = x (without the absolute value sign):
This is the graph of f(x) = |x| :