Answer:
(-∞, 4)
Explanation:
A function is decreasing when its slope (derivative) is negative, meaning that as x increases, y decreases.
The graphed function shows an upward-opening parabola with a vertex (turning point) at (4, -1).
For an upward-opening parabola, the function is:
- Decreasing when x is less than the x-value of the vertex (to the left of the vertex).
- Increasing when x is greater than the x-value of the vertex (to the right of the vertex).
As the domain of the graphed parabola is unrestricted (indicated by the arrows at the endpoints of the curve), the domain on which the graphed function is decreasing is (-∞, 4).