1. **Stating the problem:** We need to simplify the expressions using the rules of exponents.
2. **Recall the exponent rules:**
- $a^m \cdot a^n = a^{m+n}$
- $\frac{a^m}{a^n} = a^{m-n}$
- $(a^m)^n = a^{m \cdot n}$
- $a^{-m} = \frac{1}{a^m}$
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### a) Simplify $6^4 \cdot 6 \cdot 6^{-4}$
3. Combine the powers of 6 by adding exponents:
$$6^4 \cdot 6^1 \cdot 6^{-4} = 6^{4+1-4}$$
4. Simplify the exponent:
$$6^{\cancel{4}+1-\cancel{4}} = 6^1 = 6$$
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### b) Simplify $\frac{5^6 \cdot 5^{-3}}{5^2 \cdot 5}$
5. Simplify numerator by adding exponents:
$$5^{6 + (-3)} = 5^3$$
6. Simplify denominator by adding exponents:
$$5^{2 + 1} = 5^3$$
7. Write the fraction:
$$\frac{5^3}{5^3} = 5^{3-3} = 5^0$$
8. Recall $5^0 = 1$
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### c) Simplify $\frac{(3b)^2 \cdot b^3 \cdot a^{-4}}{b^5 \cdot a^{-5}}$
9. Expand $(3b)^2$:
$$(3b)^2 = 3^2 \cdot b^2 = 9b^2$$
10. Substitute back:
$$\frac{9b^2 \cdot b^3 \cdot a^{-4}}{b^5 \cdot a^{-5}} = \frac{9b^{2+3} a^{-4}}{b^5 a^{-5}} = \frac{9b^5 a^{-4}}{b^5 a^{-5}}$$
11. Simplify $b$ terms:
$$\frac{9 \cancel{b^5} a^{-4}}{\cancel{b^5} a^{-5}} = 9 \cdot \frac{a^{-4}}{a^{-5}} = 9 a^{-4 - (-5)} = 9 a^{1} = 9a$$
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**Final answers:**
- a) $6$
- b) $1$
- c) $9a$
Exponent Simplification D51278
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