Solving a quadratic inequality using a calculator and online homework platform.

- Move all terms to one side: $x^2 - x - 24 - x + 9 \geq 0$
- Simplify: $x^2 - 2x - 15 \geq 0$
- Factor the quadratic: $(x - 5)(x + 3) \geq 0$
- Find the critical points by setting each factor to zero: $x = 5$ and $x = -3$
- Test intervals determined by the critical points: $(-\infty, -3)$, $(-3, 5)$, $(5, \infty)$
- The inequality holds when the product is non-negative, which occurs in $(-\infty, -3]$ and $[5, \infty)$
- Include endpoints since the inequality is "greater than or equal to"

The solution set is $(-\infty, -3] \cup [5, \infty)$