Answer:
All real numbers less than or equal to 4.
f(x) ≤ 4
Interval notation: (-∞, 4]
Explanation:
Given the quadratic function, f(x) = -(x + 5)(x + 1), where the vertex occurs at point, (-3, 4):
Since the graph of the parabola opens down, then it means that the vertex is its maximum point. In reference to the vertical points on the graph (i.e., the range values), then the vertex sets the maximum range value of k = 4. This implies that the maximum possible range value is from negative infinity to positive 4.
Therefore, the range of the function is: all real numbers less than to or equal to 4.
f(x) ≤ 4
Interval notation: (- ∞, 4]