Name ________________________________________ Date __________________ Class __________________
LESSON
3-1
Quadratic Functions in Vertex Form
Practice and Problem Solving: C
For each function, (a) write the function in vertex form. Then identify
the (b) axis of symmetry, (c) vertex, and (d) intervals where the
function is increasing or decreasing. Graph the function.
1. f ( x ) = −2 x 2 − 12 x − 17
a. Vertex form
_________________
b. Axis of symmetry
_________________
c. Vertex
_________________
d. Increasing on
_________________
Decreasing on
2. f ( x ) =
_________________
x2
+ 2x + 4
2
a. Vertex form
_________________
b. Axis of symmetry
_________________
c. Vertex
_________________
d. Increasing on
_________________
Decreasing on
_________________
An airline sells a 3-day vacation package. Sales from this
vacation package can be modeled by the quadratic function
s ( p) = −40 p 2 + 32,000 p. Sales are dependent on the price, p, of the
package. If the price is set too high, the package won’t sell, but if the
price is too low, prospective buyers will think it is a scam.
3. Complete the square to write the function in vertex form.
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4. At what price, p, does the company have the greatest revenue?
_________________________________________________________________________________________
5. What are the maximum sales possible based on this model?
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6. What is the revenue from the vacation package if the price is set at $800?
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