college algebra
posted by cyn .
The number of tickets sold each day for an upcoming performance of Handel's Messiah is given by N(x)=0.4x^2+12x+10, 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?

N(x)=.4( x^2 30 x 25)
N(x)=.4( x^230x+225250)
N(x)=.4( x15)^2 +.4(250)
so the maximum is at x=15
You solve for N(15).
Also, I recommend you graph this on your graphing calc, to see if it is correct.