1. **State the problem:**
We are given a parabola with vertex at $(-6, 2)$ and a point $(-8, -4)$ on the parabola. We want to find the equation of the parabola in vertex form, zero form, and standard form.
2. **Vertex form:**
The vertex form of a parabola is given by:
$$y = a(x - h)^2 + k$$
where $(h, k)$ is the vertex.
Here, $h = -6$ and $k = 2$, so:
$$y = a(x + 6)^2 + 2$$
3. **Find $a$ using the point $(-8, -4)$:**
Substitute $x = -8$ and $y = -4$:
$$-4 = a(-8 + 6)^2 + 2$$
$$-4 = a(-2)^2 + 2$$
$$-4 = 4a + 2$$
Subtract 2 from both sides:
$$-4 - 2 = 4a$$
$$-6 = 4a$$
Divide both sides by 4:
$$a = \frac{\cancel{-6}}{\cancel{4}} = -\frac{3}{2}$$
4. **Vertex form equation:**
$$y = -\frac{3}{2}(x + 6)^2 + 2$$
5. **Zero form:**
The zero form is:
$$y = a(x - s)(x - t)$$
We know $a = -\frac{3}{2}$ and one root is $s = -6$ (since vertex is at $x = -6$ and parabola is symmetric, the vertex is midpoint of roots).
Find the other root $t$ using the point $(-8, -4)$:
The vertex $x$-coordinate is midpoint:
$$-6 = \frac{-8 + t}{2}$$
Multiply both sides by 2:
$$-12 = -8 + t$$
Add 8 to both sides:
$$t = -12 + 8 = -4$$
6. **Zero form equation:**
$$y = -\frac{3}{2}(x + 8)(x + 4)$$
7. **Standard form:**
Expand zero form:
$$y = -\frac{3}{2}(x^2 + 4x + 8x + 32)$$
$$y = -\frac{3}{2}(x^2 + 12x + 32)$$
Distribute $-\frac{3}{2}$:
$$y = -\frac{3}{2}x^2 - 18x - 48$$
**Final answers:**
- Vertex form: $$y = -\frac{3}{2}(x + 6)^2 + 2$$
- Zero form: $$y = -\frac{3}{2}(x + 8)(x + 4)$$
- Standard form: $$y = -\frac{3}{2}x^2 - 18x - 48$$
Parabola Forms 8F6C38
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