1. The problem asks to determine the domain on which the given function is decreasing. 2. From the description, the function is a parabola opening upwards with vertex at approximately $(3.5, -3)$. 3. For a parabola $y = a(x - h)^2 + k$ opening upwards, the function decreases on the interval to the left of the vertex $x = h$ and increases to the right. 4. Since the vertex is at $x = 3.5$, the function is decreasing on the domain $$(-\infty, 3.5)$$. 5. Therefore, the function decreases for all $x$ values less than $3.5$. Final answer: The function is decreasing on the interval $$(-\infty, 3.5)$$.