Question

PLEASE HELP ME URGENT 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

since the range is increasing then the graph must be openning up and we can also prove this by saying that this graph has an absoulte minimum at y=4
then it must not have any absoulte maximum sice parobals only have one extrema

Answer 2

The minimum of the range is when x = 4 and the maximum  is when the function is + infinity  ;  therefore the graph  which is U shaped must open upwards.