Choice A is the correct answer. Rewrite with base 3.

1. Rewrite: $27 = 3^3$, so $27^{2x} = (3^3)^{2x}$.
2. Power rule: $(a^m)^n = a^{mn}$, so $(3^3)^{2x} = 3^{6x}$.
3. Verify Choice B: $9^{3x} = (3^2)^{3x} = 3^{6x}$ ✓ (Also equivalent!)

💡 Strategic Tip: Multiple representations can be correct—check all options.

Choice C is incorrect because$3^{3x} = (3^3)^x = 27^x eq 27^{2x}$. Choice D is incorrect because$81^x = (3^4)^x = 3^{4x} eq 3^{6x}$.