ANSWER
The maximum y-value is 0.
EXPLANATION
The domain of the given absolute value function is (-∞, ∞) .
This means the function is defined for all real values of x.
The range of the function is (-∞, 0].
This can be rewritten as
This means that, the highest y-value on the gray of this absolute value function is 0.
Hence the maximum y-value of the function is 0.