1. Quadratic
Inequalities

2. Quadratic Inequality
2 ways to solve:
1 ­ graph the inequality and find the region
2 ­ use quot;signquot; diagram to find solution

4. Solve by graphing:
1. Graph the inequality using the same rules for the
boundary line as used with linear inequalities
2. Test one point on each side of the boundary line to
determine the range that is true for the inequality.
3. Shade in the range

5. Sign Diagram
1. Determine the zeros of the function and place them on
a number line.
2. Use open circles for > or <
3. Use solid circles for or

6. 4. Test one value of x for each interval determined by
the zeros
5. Determine the intervals for which values are true
for the inequality
10
8 9
­10 ­2 ­1 0 1 2
­9 ­8 ­7 ­6 ­5 ­4 ­3 3 4 5 6 7

7. x2 + x + 1 > 0

9. 10
8 9
­10 ­2 ­1 0 1 2
­9 ­8 ­7 ­6 ­5 ­4 ­3 3 4 5 6 7

11. 10
8 9
­10 ­2 ­1 0 1 2
­9 ­8 ­7 ­6 ­5 ­4 ­3 3 4 5 6 7

12. Exercise 28
Questions 1-3