1. **State the problem:** We are given the function $$y = -\frac{1}{128} \cdot 4^{3(x+2)} + 30$$ and want to understand its behavior and graph.
2. **Recall the general form:** The function is of the form $$y = a \cdot c^{x} + k$$ where:
- $a$ is the vertical stretch/compression and reflection factor,
- $c$ is the base of the exponential,
- $k$ is the vertical shift.
3. **Identify parameters:** Here,
- $a = -\frac{1}{128}$ (negative, so reflection over x-axis and very small magnitude),
- $c = 4^{3} = 64$ because $4^{3(x+2)} = (4^3)^{x+2} = 64^{x+2}$,
- $k = 30$ (vertical shift upwards by 30).
4. **Rewrite the function:**
$$y = -\frac{1}{128} \cdot 64^{x+2} + 30$$
5. **Analyze behavior:**
- As $x \to \infty$, $64^{x+2} \to \infty$, so $y \to -\infty$ because of the negative coefficient.
- As $x \to -\infty$, $64^{x+2} \to 0$, so $y \to 30$ from below.
6. **Find y-intercept:** Set $x=0$:
$$y = -\frac{1}{128} \cdot 64^{2} + 30 = -\frac{1}{128} \cdot 4096 + 30 = -32 + 30 = -2$$
7. **Horizontal asymptote:** $y = 30$
**Final answer:** The function is an exponential decay reflected over the x-axis, shifted up by 30, with horizontal asymptote $y=30$ and y-intercept at $(0,-2)$.
Exponential Function 03Db20
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