5. Quadratic Inequalities
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Solve the related quadratic equation, plot the solutions on a number line, and test a value from each interval.
{ x| - 3.43 < x < 0.097 }
To solve the quadratic inequality algebraically, we will follow three steps.
Substitute values
| x=10±sqrt(112)/- 6 | |
|---|---|
| x=10 + sqrt(112)/- 6 | x=10 - sqrt(112)/- 6 |
| x=- 5/3-2sqrt(7)/3 | x=- 5/3+2sqrt(7)/3 |
| x≈ - 3.43 | x≈ 0.097 |
The solutions of the related equation are approximately - 3.43 and 0.097. Let's plot them on a number line. Since the original is a strict inequality, the points will be open.
| Interval | Test Value | Statement | Is It Part of the Solution? |
|---|---|---|---|
| - 3.43 < x < 0.097 | 0 | 0 > - 1 ✓ | Yes |
| x > 0.097 | 1 | - 13 ≯ - 1 * | No |
We can now write the solution set. { x| - 3.43 < x < 0.097 } or (- 3.43, 0.097) Finally, we can show the solution set on a number line.