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Solve the related quadratic equation, plot the solutions on a number line, and test a value from each interval.
{ x| x < - 5 or x>- 1 }
To solve the quadratic inequality algebraically, we will follow three steps.
Substitute values
x = - 6 ± 4/2 | |
---|---|
x = - 6 + 4/2 | x = - 6 - 4/2 |
x = - 2/2 | x = - 10/2 |
x = - 1 | x = - 5 |
The solutions of the related equation are - 1 and - 5. 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? |
---|---|---|---|
- 5 < x < - 1 | - 2 | - 8 ≯ - 5 * | No |
x > - 1 | 0 | 0 > - 5 ✓ | Yes |
We can now write the solution set and show it on a number line. { x| x < - 5 or x>- 1 } or (- ∞, - 5) ⋃ (- 1, ∞)