Question

The number of tickets sold each day for an upcoming performance is given by N(x)= -0.4x^2 +8x +15, 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? Tickets will peak __ days after the concert was first announced. The number of tickets sold on that day will be __.

Answer 1

okay, we can do this problem very easy way

Answer 2

ok

Answer 3

okay, so we will use a simply formula to find the vertex or center of the downward opening parabola that the function N(x)= -0.4x^2 +8x +15 describes

Answer 4

okay

Answer 5

we will use this formula, x=(-b)/(2a), this formula will give us the vertex of the parabola

Answer 6

now in this case, a=-0.4 and b=8

Answer 7

now can you plug those two numbers into the formula and evluate it?

Answer 8

20?

Answer 9

check again because i got 10

Answer 10

oh

Answer 11

did you check you work for a mistake?

Answer 12

no

Answer 13

why not?

Answer 14

no clue how. I always forget

Answer 15

okay, well then i think you can solve the rest of the problem from here