1. **State the problem:** Find the roots and vertex of the quadratic function $$y = -x^2 + 12x - 11$$.
2. **Formula for roots:** The roots of a quadratic $$ax^2 + bx + c = 0$$ are given by the quadratic formula:
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
where $$a = -1$$, $$b = 12$$, and $$c = -11$$.
3. **Calculate the discriminant:**
$$\Delta = b^2 - 4ac = 12^2 - 4(-1)(-11) = 144 - 44 = 100$$
4. **Find the roots:**
$$x = \frac{-12 \pm \sqrt{100}}{2(-1)} = \frac{-12 \pm 10}{-2}$$
5. **Calculate each root:**
- For the plus sign:
$$x_1 = \frac{-12 + 10}{-2} = \frac{-2}{-2} = 1$$
- For the minus sign:
$$x_2 = \frac{-12 - 10}{-2} = \frac{-22}{-2} = 11$$
6. **Formula for vertex:** The vertex $$ (h, k) $$ of a parabola $$y = ax^2 + bx + c$$ is given by:
$$h = -\frac{b}{2a}$$
$$k = f(h) = a h^2 + b h + c$$
7. **Calculate vertex x-coordinate:**
$$h = -\frac{12}{2(-1)} = -\frac{12}{-2} = 6$$
8. **Calculate vertex y-coordinate:**
$$k = - (6)^2 + 12(6) - 11 = -36 + 72 - 11 = 25$$
9. **Final answers:**
- Roots: $$1$$ and $$11$$
- Vertex: $$(6, 25)$$
The parabola opens downward because $$a = -1 < 0$$, so the vertex is a maximum point.
Roots Vertex C8541E
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