Question 1114189
{{{ N(x) = -.5x^2 + 11x + 11 }}}
If the form of the quadratic is:
{{{ y = a*x^2 + b*x + c }}}, then the
x-value of the
vertex ( peak in your case ) is at
{{{ x[v] = -b/(2a) }}}
{{{ a = -.5 }}}
{{{ b = 11 }}}
-------------------
{{{ x[v] = -11/(2*(-.5)) }}}
{{{ x[v] = 11 }}}
Now find {{{ N(11) }}}
{{{ N(11) = -.5*11^2 + 11*11 + 11 }}}
{{{ N(11) = -55.5 + 121 + 11 }}}
{{{ N(11) = 132 - 55.5 }}}
{{{ N(11) = 76.5 }}}
Ticket sales will peak 77 days after concert was announced
( check the math )