1. **State the problem:** We need to find the equation that represents the water level $w$ after $d$ days based on the given data points: $(3, 96)$, $(6, 90)$, $(9, 84)$, $(12, 78)$, $(15, 72)$.
2. **Identify the pattern:** The water level decreases as days increase, suggesting a linear relationship of the form $$w = md + b$$ where $m$ is the slope and $b$ is the initial water level.
3. **Calculate the slope $m$:** Use two points, for example $(3, 96)$ and $(6, 90)$.
$$m = \frac{90 - 96}{6 - 3} = \frac{-6}{3} = -2$$
4. **Find the y-intercept $b$:** Use the point-slope form with point $(3, 96)$:
$$96 = -2(3) + b$$
$$96 = -6 + b$$
$$b = 96 + 6 = 102$$
5. **Write the equation:**
$$w = -2d + 102$$
6. **Check the options:**
- A: $w = 2x + 102$ (incorrect slope sign)
- B: $w = -102x + 2$ (incorrect slope and intercept)
- C: $w = 102x - 2$ (incorrect slope and intercept)
The correct equation is $w = -2d + 102$, which matches option A if $x$ is replaced by $d$ and the slope sign corrected. Since none exactly match, the closest correct form is option A with corrected slope sign.
**Final answer:**
$$w = -2d + 102$$
Water Level 7A7Baa
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