quad inequal apr 17 09

Quadratic

Inequalities

Quadratic Inequality

2 ways to solve:

1 graph the inequality and find the region

2 use "sign" diagram to find solution

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

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

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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

x2 + x + 1 > 0

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Exercise 28

Questions 1 - 3

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