1. **State the problem:** Find the roots and vertex of the quadratic function $$y = -x^2 - 16x + 36$$.
2. **Formula for roots:** Use the quadratic formula $$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$ where $$a = -1$$, $$b = -16$$, and $$c = 36$$.
3. **Calculate the discriminant:** $$\Delta = b^2 - 4ac = (-16)^2 - 4(-1)(36) = 256 + 144 = 400$$.
4. **Calculate the roots:**
$$x = \frac{-(-16) \pm \sqrt{400}}{2(-1)} = \frac{16 \pm 20}{-2}$$
5. **Evaluate each root:**
- For the plus sign: $$x = \frac{16 + 20}{-2} = \frac{36}{-2} = -18$$
- For the minus sign: $$x = \frac{16 - 20}{-2} = \frac{-4}{-2} = 2$$
6. **Formula for vertex:** The vertex $$x$$-coordinate is $$x = -\frac{b}{2a}$$.
7. **Calculate vertex $$x$$-coordinate:**
$$x = -\frac{-16}{2(-1)} = \frac{16}{-2} = -8$$
8. **Calculate vertex $$y$$-coordinate:** Substitute $$x = -8$$ into the original equation:
$$y = -(-8)^2 - 16(-8) + 36 = -64 + 128 + 36 = 100$$
9. **Final answers:**
- Roots: $$-18$$ and $$2$$
- Vertex: $$(-8, 100)$$
Quadratic Roots Vertex Ba3913
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