1. **State the problem:** Determine which statement is true among the following comparisons involving exponents:
$$\frac{3^{-15}}{3^{7}} \quad \text{and} \quad (3^{-8}) \cdot (3^{-9})$$
Options:
- A: $$\frac{3^{-15}}{3^{7}} < (3^{-8}) \cdot (3^{-9})$$
- B: $$\frac{3^{-15}}{3^{7}} > (3^{-8}) \cdot (3^{-9})$$
- C: $$\frac{3^{-15}}{3^{7}} = (3^{-8}) \cdot (3^{-9})$$
2. **Recall exponent rules:**
- Division of same bases: $$\frac{a^{m}}{a^{n}} = a^{m-n}$$
- Multiplication of same bases: $$a^{m} \cdot a^{n} = a^{m+n}$$
3. **Simplify the left side:**
$$\frac{3^{-15}}{3^{7}} = 3^{-15 - 7} = 3^{-22}$$
4. **Simplify the right side:**
$$(3^{-8}) \cdot (3^{-9}) = 3^{-8 + (-9)} = 3^{-17}$$
5. **Compare the two expressions:**
We have $$3^{-22}$$ and $$3^{-17}$$.
Since the base 3 is greater than 1, the function $$3^{x}$$ is increasing, so the smaller exponent corresponds to a smaller value.
Because $$-22 < -17$$, it follows that:
$$3^{-22} < 3^{-17}$$
6. **Conclusion:**
$$\frac{3^{-15}}{3^{7}} = 3^{-22} < 3^{-17} = (3^{-8}) \cdot (3^{-9})$$
Therefore, **Option A is true.**
Exponent Comparison 6008B7
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