Question 460257
Tickets sold = -0.2x^2+12x+11
x=1 is the day tickets go on sale.
 Use the quadratic equation to determine the last day tickets will be sold.
 I replaced x with 1 in the equation above to determine 22.8 tickets were sold
 on day one, but I'm not sure that is correct.
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That is correct, but since you can't have a fraction of ticket is would be 23 ticket on day 1
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How do I find out the last day tickets were sold? 
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That would be when the tickets sold = 0, this is quadratic equation that will
peak and then return thru 0
:
 -0.2x^2 + 12x + 11 = 0
you will have to use the quadratic formula to find x
{{{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 + 12.33)/(-.4) }}}
x = {{{.33/(-.4)}}}
x = -.825, obviously this is not our solution
and
{{{x = (-12 - 12.33)/(-.4) }}}
x = {{{(-24.33)/(-.4)}}}
x = +60.825 ~ 61 days for 0 tickets to be sold
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You can substitute 60.825 for x in the original equation and prove it to yourself
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Did this make sense to you?