Question: (2^x)^-6(8^x) =
A. 2^-3x.
B. 2^-5x.
C. 2^4x-6.
D. 4^-x.
1. **State the problem:** Simplify the expression $$(2^x)^{-6} (8^x)$$.
2. **Recall the exponent rules:**
- Power of a power: $$(a^m)^n = a^{mn}$$
- Product of powers with the same base: $$a^m \cdot a^n = a^{m+n}$$
- Express numbers as powers of the same base if possible.
3. **Rewrite each term:**
- $$(2^x)^{-6} = 2^{x \cdot (-6)} = 2^{-6x}$$
- Note that $$8 = 2^3$$, so $$8^x = (2^3)^x = 2^{3x}$$
4. **Multiply the terms:**
$$2^{-6x} \cdot 2^{3x} = 2^{-6x + 3x} = 2^{-3x}$$
5. **Final answer:**
The expression simplifies to $$2^{-3x}$$, which corresponds to option A.
**Answer:** A. $2^{-3x}$