Question

A quadratic function is decreasing on (-∞, 3) and increasing on (3, ∞).
Will the vertex be the highest or lowest point on the graph of the parabola?
Explain.

Answer 1

Greetings from Brasil...

If X grows and Y grows, the function is increasing

If X increases and Y decreases, the function is decreasing

Besides that, according to the statement, we can conclude that the parabola has an upward concavity, that is, a > 0. In this case the vertex will be a minimum point

check the attachments

P.S. - vertex coordinate = (3; 0)