1. How does the value of a affect the graphs?
Visual Warm up
How does the value of a affect the graphs?

2. How does the value of b affect the graph?
Visual warm up
How does the value of b affect the graph?

3. How does the value of c affect the graph?
Visual warm up
How does the value of c affect the graph?

4. 9.3 Graphing Quadratic Functions
To graph quadratic equations on a coordinate plane.
Objective:
VOCABULARY
Every quadratic function has a U-shaped graph called a parabola.
The vertex of a parabola is the lowest point (minimum) of a parabola that opens up and the highest point (maximum) of a parabola that opens down.
The axis of symmetry of a parabola is the vertical line passing through the vertex.

5. Parts of a parabola Vertex Axis of Symmetry y-intercept
x-intercept (root)
X-intercept (root)
Vertex

6. If a is positive, the parabola opens up.
GRAPH OF A QUADRATIC FUNCTION
The graph of y = ax2 + bx + c is a parabola.
If a is positive, the parabola opens up.
If a is negative, the parabola opens down.
The vertex has an x-coordinate of –b a
The axis of symmetry is the vertical line x = –b a
The y-intercept is c.

7. GRAPHING A QUADRATIC FUNCTION
Step 1: Find the x-coordinate of the vertex.
Step 2: Make a table of values, using x-values to the left and right of the vertex.
Step 3: Plot the points and connect them with a smooth curve to form a parabola.

8. Graph x y a = 1 b = –2 c = –3 -2 -1 1 2 3 4 5 -3 -4 -3 5
The x-coordinate of the vertex is
Make a table using 1 in the middle, and points to the left and right. Complete the table
The axis of symmetry is the line x = 1
The vertex is (1,-4) x y -2 -1 1 2 3 4 5 -3 -4 -3 5