1. **State the problem:** Solve the inequality $$-x^2 + 6x \leq 5$$ and graph the solution on the number line.
2. **Rewrite the inequality:** Move all terms to one side to set the inequality to zero:
$$-x^2 + 6x - 5 \leq 0$$
3. **Multiply both sides by -1** to make the quadratic coefficient positive. Remember to reverse the inequality sign when multiplying by a negative number:
$$\cancel{-1}(-x^2 + 6x - 5) \geq \cancel{-1}(0)$$
which simplifies to
$$x^2 - 6x + 5 \geq 0$$
4. **Factor the quadratic:**
$$x^2 - 6x + 5 = (x - 1)(x - 5)$$
5. **Analyze the inequality:**
We want to find where
$$(x - 1)(x - 5) \geq 0$$
6. **Determine intervals:**
The critical points are $x=1$ and $x=5$. Test intervals:
- For $x < 1$, pick $x=0$: $(0-1)(0-5) = (-1)(-5) = 5 \geq 0$ (True)
- For $1 < x < 5$, pick $x=3$: $(3-1)(3-5) = (2)(-2) = -4 \geq 0$ (False)
- For $x > 5$, pick $x=6$: $(6-1)(6-5) = (5)(1) = 5 \geq 0$ (True)
7. **Write the solution set:**
$$(-\infty, 1] \cup [5, \infty)$$
8. **Interpretation:**
The solution includes all $x$ values less than or equal to 1 and greater than or equal to 5.
**Final answer:**
$$\boxed{(-\infty, 1] \cup [5, \infty)}$$
Quadratic Inequality B91Cbe
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