The local amusement park charges $18.95 per person. however , after 5pm the charge is reduced to $14.45 per person. a group of 4 adults is planning to go to the park. how much would they save if they go after 5 pm?

The would save $18. Here are the steps:
First, multiply 18.95×4=75.8 <--this is how much it cost for 4 adults BEFORE 5pm.
Second, multiply 14.45×4=57.8 <--this is how much it costs after the price is reduced at 5pm.
Lastly, you subtract the products: 75.8-57.8=18
So, therefore the adults would save $18 if they go after 5pm.

Do you need with the x value for the minimum? its always between the two intercepts for a parabola