Vertex Parabola 3E12D9
1. **Stating the problem:**
We are given the quadratic function $$y = x^2 - 2x - 8$$ and asked to find:
a. The coordinates of the vertex (titik puncak).
b. The graph of the function.
2. **Formula for the vertex of a parabola:**
For a quadratic function $$y = ax^2 + bx + c$$, the x-coordinate of the vertex is given by:
$$x = -\frac{b}{2a}$$
The y-coordinate is found by substituting this x back into the function.
3. **Identify coefficients:**
Here, $$a = 1$$, $$b = -2$$, and $$c = -8$$.
4. **Calculate the x-coordinate of the vertex:**
$$x = -\frac{-2}{2 \times 1} = \frac{2}{2} = 1$$
5. **Calculate the y-coordinate of the vertex:**
Substitute $$x=1$$ into the function:
$$y = (1)^2 - 2(1) - 8 = 1 - 2 - 8 = -9$$
6. **Vertex coordinates:**
The vertex is at $$ (1, -9) $$.
7. **Graph description:**
The parabola opens upwards (since $$a=1 > 0$$) with vertex at $$ (1, -9) $$.
8. **Summary:**
- Vertex: $$ (1, -9) $$
- Equation: $$y = x^2 - 2x - 8$$
This completes the solution for the vertex and the graph description.