1. **State the problem:** We need to find the vertex, axis of symmetry, and y-intercept of a parabola.
2. **Given information:** The vertex is at $(2, -1)$.
3. **Axis of symmetry:** The axis of symmetry of a parabola is a vertical line passing through the vertex. Since the vertex is at $x=2$, the axis of symmetry is:
$$x=2$$
4. **Y-intercept:** The y-intercept is the point where the graph crosses the y-axis, i.e., where $x=0$.
5. **Find the y-intercept:** Using the vertex form of a parabola:
$$y = a(x - h)^2 + k$$
where $(h, k)$ is the vertex. Here, $h=2$ and $k=-1$.
6. **Find $a$ using the y-intercept:** The parabola crosses the y-axis at approximately $y=3$ when $x=0$.
Substitute $x=0$, $y=3$:
$$3 = a(0 - 2)^2 - 1$$
$$3 = a(4) - 1$$
$$3 + 1 = 4a$$
$$4 = 4a$$
$$a = 1$$
7. **Equation of the parabola:**
$$y = 1(x - 2)^2 - 1 = (x - 2)^2 - 1$$
8. **Confirm y-intercept:** Substitute $x=0$:
$$y = (0 - 2)^2 - 1 = 4 - 1 = 3$$
So the y-intercept is $(0, 3)$.
**Final answers:**
- Vertex: $(2, -1)$
- Axis of symmetry: $x=2$
- Y-intercept: $(0, 3)$
Parabola Properties A2Fa8E
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