1. **State the problem:**
Given a downward-opening parabola with vertex approximately at $(-3,4)$, axis of symmetry $x=-3$, and zeros at $(-5,0)$ and $(-1,0)$, identify the axis of symmetry, vertex, domain, range, zeros, and the correct equation from the options.
2. **Axis of symmetry formula:**
For a parabola $y = ax^2 + bx + c$, the axis of symmetry is given by
$$x = -\frac{b}{2a}$$
3. **Vertex:**
The vertex is at $(h,k)$ where $h$ is the axis of symmetry and $k$ is the value of $y$ at $x=h$.
4. **Domain:**
The domain of any quadratic function is all real numbers:
$$\text{Domain} = (-\infty, \infty)$$
5. **Range:**
Since the parabola opens downward (as given), the range is all $y$ values less than or equal to the vertex's $y$-coordinate:
$$\text{Range} = (-\infty, 4]$$
6. **Zeros:**
The zeros are the $x$-intercepts where $y=0$, given approximately as $-5$ and $-1$.
7. **Identify the equation:**
Check each option's axis of symmetry and vertex:
- Option A: $y = x^2 + 6x - 5$
- $a=1$, $b=6$
- Axis: $x = -\frac{6}{2(1)} = -3$
- Vertex $y$-value: $y(-3) = (-3)^2 + 6(-3) - 5 = 9 - 18 - 5 = -14$
- Vertex is $(-3, -14)$, which does not match.
- Option B: $y = x^2 - 6x - 5$
- $a=1$, $b=-6$
- Axis: $x = -\frac{-6}{2(1)} = 3$
- Vertex $y$-value: $y(3) = 9 - 18 - 5 = -14$
- Vertex is $(3, -14)$, does not match.
- Option C: $y = -x^2 + 6x - 5$
- $a=-1$, $b=6$
- Axis: $x = -\frac{6}{2(-1)} = -\frac{6}{-2} = 3$
- Vertex $y$-value: $y(3) = -(3)^2 + 6(3) - 5 = -9 + 18 - 5 = 4$
- Vertex is $(3,4)$, but given vertex is $(-3,4)$, so no.
- Option D: $y = -x^2 - 6x - 5$
- $a=-1$, $b=-6$
- Axis: $x = -\frac{-6}{2(-1)} = -\frac{-6}{-2} = -3$
- Vertex $y$-value: $y(-3) = -(-3)^2 - 6(-3) - 5 = -9 + 18 - 5 = 4$
- Vertex is $(-3,4)$, matches perfectly.
8. **Final answers:**
- Axis of Symmetry: $x = -3$
- Vertex: $(-3, 4)$
- Domain: $(-\infty, \infty)$
- Range: $(-\infty, 4]$
- Zeros: $-5$ and $-1$
- Equation: $y = -x^2 - 6x - 5$ (Option D)
Parabola Properties 1D2204
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