I would do it in Buhh I'm working so add all of them(16,18,20) together 6 times then add another 16 and 18 and you will get your answer.

The Quadratic Function has the domain as the set of all real numbers.
For the range, start from minimum value to maximum value.
But because the parabola is downward as a < 0. Thus, there are no minimum value but the maximum value instead.
Therefore the range is y <= -4
If Carla would have bought 4 plants it would have been 13 dollars from green touch
If she would have bought them for the grocery store it would have been 14 dollars
So in conclusion she saved 1 dollar
Option 3