1. 4.9 Graph and Solve Quadratic Inequalities

2. In this lesson we will graph Quadratic Inequalities like the following:.
1. Graph the parabola:
Since the inequality symbol is >, make the parabola dashed.
2. Test a point inside the parabola, such as (1,0)
3. Since 0 > -4 is TRUE, shade the region inside the parabola.

3. Is the ordered pair (4, 4) a solution to the quadratic inequality:

4. Sketch the inequality:

5. Graphing a system of Quadratic Inequalities.
Graph the system:
Can you locate the region that contains the solutions to the system?

6. Now we will consider how a graph can help us solve a quadratic inequality in one variable.
First, graph the parabola. 1 5
Locate the x-intercepts.
Notice the x values for which the parabola is less than 0 (lies below the x-axis)
These are the values for x which satisfy the quadratic inequality: 1 < x < 5

7. Solve: