Question

The graph of a quadratic function has a domain of (-∞, ∞) and range of [4, ∞). In two or more complete sentences, explain how the given range of the function can help you to determine whether the graph opens up or down.

Answer 1

The given range can help us to determine whether the graph of a quadratic function opens up or down.
If the range is [ 4, + ∞ ) it has a minimum point with coordinates ( x, 4 ). The vertex is the lowest point on the graph.
Answer: The graph opens up.