SOLUTION: Could you please help me in understanding this problem. I have attempted to use the formulas x=-b/2a and 4ac-b^2/4a. However the answers I have received to not seem to fit. Am I no

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Could you please help me in understanding this problem. I have attempted to use the formulas x=-b/2a and 4ac-b^2/4a. However the answers I have received to not seem to fit. Am I no      Log On


   

Question 177148: Could you please help me in understanding this problem. I have attempted to use the formulas x=-b/2a and 4ac-b^2/4a. However the answers I have received to not seem to fit. Am I not supposed to use that formula? There are several parts to this problem a-i and I am nervous to start off with the wrong answer as it would mean that could affect all the answers that come after part a. Any help you can give me will be very much appreciated.
The problem:
1. Suppose you are an event coordinator for a large performance theater. One of the hottest new Broadway musicals has started to tour, and your city is the first stop on the tour. You need to supply information about projected ticket sales to the box office manager. The box office manager uses this information to anticipate staffing needs until the tickets sell out. You provide the manager with a quadratic equation that models the expected number of ticket sales for each day x. ( x=1 is the day tickets go on sale).
Tickets =-0.2x^2+12x+11

a. Does the graph of this equation open up or down? How did you determine this?

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Notice how -0.2x%5E2%2B12x%2B11 is of the form ax%5E2%2Bbx%2Bc where a=-0.2, b=12, and c=11


Since a%3C0, this tells us that the parabola opens down (remember, the coefficient "a" determines whether it opens up or down). So the parabola looks similar to this:



Note: this is NOT the graph of -0.2x%5E2%2B12x%2B11, but the parabola opens in the same direction as -0.2x%5E2%2B12x%2B11


So this means that the graph has a maximum.