To solve this, let's set the two exponents so that they have the same base. We know that 9 is 3², so we can rewrite the left side as (3²)^(x-8), which simplifies to 3^(2x-16). Now, we have 3^(2x-16) = 3^(4x-12). Since the bases are equal, the exponents are also equal. Therefore, 2x-16 = 4x-12. When we solve, we get -2x = 4, so x=-2. Hope this helps!