Algebra 2 Notes
March 3, 2009


An engineer collects the following
data showing the speed in miles per
hour (x) of a Ford Taurus and its
average miles per gallon (y)
1) Using your calculator generate a
scatter plot of the data and find the
quadratic function of best fit.
◦ Use the calc. steps given in the notes yesterday

2) Use the function to predict the
miles per gallon for a speed of 63
miles per hour.
◦ Use your 2nd Table function to check your
answer


Remember standard form of a quadratic
function:
When a > 0 (positive)
◦ The parabola opens UP
◦ The vertex is a ___________??

When a < 0 (negative)
◦ The parabola opens DOWN
◦ The vertex is a ___________??

The graph will intersect the y-axis when x=0
◦ To find the y-intercept of a function, plug ‘0’ into
the equation for x

The equation for the line of symmetry is:
◦ This equation also gives you the x coordinate of the
vertex
8
6
4
2
-8 -7 -6 -5 -4 -3 -2 -1
-2
-4
-6
-8
1 2 3 4 5 6 7 8
8
6
4
2
-8 -7 -6 -5 -4 -3 -2 -1
-2
-4
-6
-8
1 2 3 4 5 6 7 8
Example C:
 Vertex: (0, 3)
 y-intercept: (0, 3)
Example D:
 Vertex: (4, 4)
 y-intercept: (0, 0)
Extension:
You obviously can’t hire three-fourths of an
employee, so in order to realistically
maximize profit as best you can how many
employees would you hire, 3 or 4? Explain
 Page
248 #22, 25, 28-30,
37-39