Answer:
Domain: (-∞, -5) (-1, ∞)
Explanation:
Note:
For f(x) > 0: See the points of x for which the graph of f(x) lies above the x-axis.
For f(x) < 0: See the points of x for which the graph of f(x) lies below the x-axis.
We need to find the domain of f(x) for which f(x) < 0
From the graph, we can tell:
f(x) < 0 on (-∞, -5) ∪ (-1, ∞)
Therefore: The domain on which the given graph f(x) is negative, is (-∞, -5) ∪ (-1, ∞)