1. 9-3 Graphing y = ax + bx + c up 1a. y = x - 1 for -3<x<32 2 up
1a. y = x - 1
for -3<x<3
B. Does it open up or down?
C. Identify the axis of symmetry
and its vertex.
y-axis, (0,-1) y x -3 -2 -1 1 2 3 y 8 3 -1 8
x = 0 x -4 4

2. Use the equation y = x² + 8x + 13 for x = -7, -6, -5, … 0,
to answer questions and make a table of values.
a. What is the vertex of the
parabola?
b. What is its axis of symmetry?
c. Find the y-intercept.
d. Graph it.
e. What are the x-coordinates of the
2 points where y = 13?
(-4,-3)
x = -4 y 6 1 -2 -3 13 x -7 -6 -5 -4 -3 -2 -1 ? 13
0 & -8

3. y y 6 1 -2 -3 13 x -7 -6 -5 -4 -3 -2 -1 12 8 4 x -8 -4 -4

4. To find the x value of the turning point, use this 2
3a. Graph y = .5x - 2x.
To find the x value of the turning point, use this
formula , where a is the _____________
and b is the _____________
coefficient of x 2
x = -b 2a
coefficient of x
x = -(-2) = 2 = 2
2(.5)
So, a = .5 and b = -2
Now you can make a table selecting x values that will enable you
to graph the parabola over its line or symmetry.
x y
b. Does the graph have an axis of symmetry?
If so, what is it?
c. Name the vertex.
d. Identify the y-intercept.
Yes, x = 2
(2,-2)

5. y
x y 3 2 1 x 5 -1 -2 -3