Which expression is equivalent to 3^-4 x 3^6?

To find the equivalent expression, we add the exponents together.

3^-4 x 3^6 = 3^(-4+6) = 3^2 = 9. Answer: \boxed{9}.

To find an equivalent expression to 3^-4 x 3^6, you can combine the two exponents since the bases are the same (which is 3).

When multiplying exponentials with the same base, you add the exponents. So, 3^-4 x 3^6 can be written as 3^(-4 + 6).

Simplifying the exponent, we have:

3^(-4 + 6) = 3^2

Therefore, an equivalent expression to 3^-4 x 3^6 is 3^2.

To find the equivalent expression, we can use the rule of exponents which states that when multiplying two powers with the same base, we add their exponents.

The given expression is:
3^-4 x 3^6

Using the rule of exponents, we add the exponents:
3^(-4 + 6)

Simplifying the exponent:
3^2

Therefore, the expression 3^-4 x 3^6 is equivalent to 3^2.