This is the basic absolute value function, with a negative at the front. The graph of this function is the flipped version of the positive absolute value function. It is reflected about the x-axis, with respect to the parent function y = |x|.
The range of a function is the set of y-values for which the function is defined. Looking at the function, the range is all values less than or equal to 0.
We can write the range as:
[tex]y\leq0[/tex]