1. **State the problem:** Solve the logarithmic equation $$\log_2 4 + \log_2 (c - 9) = 5$$ for $c$.
2. **Recall the logarithm property:** The sum of logarithms with the same base can be combined as the logarithm of the product:
$$\log_b A + \log_b B = \log_b (A \times B)$$
3. **Apply the property:**
$$\log_2 4 + \log_2 (c - 9) = \log_2 [4(c - 9)]$$
4. **Rewrite the equation:**
$$\log_2 [4(c - 9)] = 5$$
5. **Convert logarithmic form to exponential form:**
$$4(c - 9) = 2^5$$
6. **Calculate the right side:**
$$2^5 = 32$$
7. **Set up the equation:**
$$4(c - 9) = 32$$
8. **Divide both sides by 4:**
$$\cancel{4}(c - 9) = \frac{32}{\cancel{4}}$$
$$c - 9 = 8$$
9. **Solve for $c$:**
$$c = 8 + 9 = 17$$
10. **Check for extraneous solutions:**
The argument of the logarithm must be positive:
$$c - 9 > 0 \implies 17 - 9 = 8 > 0$$
This is valid.
**Final answer:**
$$c = 17$$
Logarithmic Equation 66A0F7
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