Question 465145
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Hi
Note: the vertex form of a parabola, {{{y=a(x-h)^2 +k}}} where(h,k) is the vertex
Tickets = -0.2x^2 + 12x + 11  |completing the Square to put into vertex form
Tickets = -0.2 [x^2 - 60] + 11 
Tickets = -0.2[(x- 30)^2 -900]+ 11 
Tickets = -0.2(x-30)^2 + 180 + 11 
Tickets = -0.2(x-30)^2 + 191 |a = -.2 < 0, parabola opens downward, vertex a max pt
e. After how many days will the peak occur? 30days
f.how many tickets will be sold on the day when the peak or low occurs? 191

using the quadratic formula to determine when Ticket Sales = 0
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
{{{x = (-12 +- sqrt( 152.8))/(-.4) }}}
 x is -0.9031(extraneous, cannot have 'minus' days), 60.9031.
i. What do the solution '61' represent? NO tickets sold on that day or after