Question 195582
 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
:
It may be helpful to actually draw this graph, then answer the questions:
{{{ graph( 300, 200, -40, 80, -50, 200, -.2x^2+12x+11) }}}
:
a) Does the graph of this equation go up or down?
You can see the graph goes upward (opens downward)
 How was this determined?
This is determined by the coefficient of x^2
Negative: opens downward, has a maximum
Positive: open upward, has a minimum
:
b) Describe what happens to the tickets as time passes?
You can see the no. of tickets increase to a maximum, then decreases to 0
:
c) Use the quadratic equation to determine the last day tickets will be sold.
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
In this equation a=-.2, b=12; c=11
{{{x = (-12 +- sqrt(12^2 - 4 * -.2 * 11 ))/(2*-.2) }}}
:
{{{x = (-12 +- sqrt(144 - (-8.8)))/(-.4) }}}
:
{{{x = (-12 +- sqrt(144 + 8.8))/(-.4) }}}
:
{{{x = (-12 +- sqrt(152.8))/(-.4) }}}
Two solutions
{{{x = (-12 - 12.36)/(-.4) }}}
{{{x = (-24.36)/(-.4) }}}
x = +60.9, no tickets sold after 60 days
and
{{{x = (-12 + 12.36)/(-.4) }}}
{{{x = (.36)/(-.4) }}}
x = -.9, this solution does not make sense
:
See if you can answer the rest of the questions by what we have done so far
Email me if you have difficulty
:
d) Will tickets peak or be at a low during the middle of the sale? How do you know?
e) After how many days will the peak or low occur?
f) How many tickets will be sold on the day when the peak or low occurs?
g) What is the point of the vertex?
h) How many solutions are there to the equation -0.2x^2 +12x+11=0
I) What do the solutions represent? Is there a solution that does not make sense? If so in what whys does the solution not make sense?