You have the correct answers.
The 'a' value determines if the parabola opens up or down
If a < 0, then the parabola opens down to form a frown
If a > 0, then the parabola opens upward to form a smile.
The closer 'a' is to zero, the more wide the parabola will be. In contrast, if 'a' is pretty far from zero, then the parabola is more skinny/narrow.
