1. **State the problem:** We have the function $y=4\sqrt{-8x+16}-11$ and want to find its vertex, domain, and range, and rewrite it in vertex form.
2. **Rewrite the function inside the square root:**
$$-8x+16 = -8(x-2)$$
3. **Express the function as:**
$$y=4\sqrt{-8(x-2)}-11$$
4. **Simplify inside the square root:** Since $\sqrt{a b} = \sqrt{a} \sqrt{b}$,
$$y=4\sqrt{-8}\sqrt{x-2}-11$$
However, $\sqrt{-8}$ is imaginary, so instead, factor out $-1$ inside the root:
$$y=4\sqrt{-1 \cdot 8(x-2)}-11=4\sqrt{-1}\sqrt{8(x-2)}-11$$
Since $\sqrt{-1}=i$ (imaginary), the function is real only if $-8x+16 \geq 0$ or $x \leq 2$.
5. **Rewrite the function to isolate the vertex:** Let’s set
$$u = -8x +16$$
The function is
$$y=4\sqrt{u} -11$$
The square root function $\sqrt{u}$ has its minimum at $u=0$, so vertex occurs when
$$-8x +16 = 0 \Rightarrow x=2$$
At $x=2$,
$$y=4\sqrt{0} -11 = -11$$
So the vertex is at $(2, -11)$.
6. **Domain:** Since the expression inside the root must be non-negative,
$$-8x +16 \geq 0 \Rightarrow x \leq 2$$
7. **Range:** The smallest value of $y$ is at the vertex $-11$, and since $\sqrt{u} \geq 0$, $y$ increases from $-11$ upwards.
So,
$$\text{Range} = [-11, \infty)$$
8. **General form:** The function is already in vertex form for a square root function:
$$y = a \sqrt{x - h} + k$$
Here,
$$a = 4\sqrt{-8}$$ is complex, so instead, keep the function as
$$y = 4\sqrt{-8(x-2)} - 11$$
or equivalently,
$$y = 4\sqrt{16 - 8x} - 11$$
with vertex at $(2, -11)$.
**Final answers:**
- Vertex: $(2, -11)$
- Domain: $(-\infty, 2]$
- Range: $[-11, \infty)$
Vertex Domain Range D36Eba
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