Question 155721
N(x)= -0.3^2+7.8x+12, where x is the number of days since the concert was first
 announced. When will daily ticket sales peak and how many tickets will be sold
 that day?
:
Notice that this is a quadratic equation, if we find the axis of symmetry we can
find the maximum (vertex);
:
Find the axis of symmetry using the formula x = -b/(2a)
In this equation it would be
x = {{{(-7.8)/(2*-.3)}}}
x = {{{(-7.8)/(-.6)}}}
x = +13 days from the announcement for max ticket sales
:
Find the max number of tickets by substituting 13 for x in the equation:
N(x)= -0.3^13^2 + 7.8(13) + 12
N(x) = -.3(169) + 101.4 + 12
N(x) = -50.7 + 101.4 + 12
N(x) = 62.7 ~ 63 is the maximum tickets sold.
:
Did this make sense to you now?