Question 89183
You can tell in the following way!
The general form of the equation of a parabola is:
{{{ax^2+bx+c = 0}}} 
Look at the coefficient of the {{{x^2}}} term, that's the a, and...
If a > 0 (positive), then the parabola opens upward and the graph has a minimum at its vertex.
If a < 0 (negative), then the parabola opens downward and the graph has a maximum at its vertex.