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| - 4.65 ≤ x ≤ 0.65 }
To solve the quadratic inequality algebraically, we will follow three steps.
Substitute values
| x=- 4±sqrt(28)/2 | |
|---|---|
| x=- 4 + sqrt(28)/2 | x=- 4 - sqrt(28)/2 |
| x=- 4/2+sqrt(28)/2 | x=- 4/2-sqrt(28)/2 |
| x≈ 0.65 | x≈ - 4.65 |
The solutions of the related equation are approximately - 4.65 and 0.65 Let's plot them on a number line. Since the original is not a strict inequality, the points will be closed.
x= - 5
Calculate power
- a(- b)=a* b
Add terms
| Interval | Test Value | Statement | Is It Part of the Solution? |
|---|---|---|---|
| - 4.65 ≤ x ≤ 0.65 | 0 | - 3 ≤ 0 ✓ | Yes |
| x ≥ 0.65 | 1 | - 3 ≰ - 5 * | No |
We can now write the solution set and show it on a number line. { x| - 4.65 ≤ x ≤ 0.65 } or [- 4.65, 0.65]