The answer is 52. remember PEMDAS (parentheses, exponents, multiplication, division, addition, subtraction) you can use "please excuse my dear aunt sally" to help you remember! :)
Let's take a look at the first few numbers in the sequence based on the given rule:

Inspecting this pattern it seems like the power

is being raised to is always one less than the number of the sequence, so if we were on the nth number in the sequence, that part of the expression would be

. We also know that we'll be multiplying whatever we get from that by 6, so we can write the full explicit rule for our sequence as

Where

is the nth number in our sequence.
To divide the expression we proceed as follows:
12x⁴y²÷3x³y⁵
=12x⁴y²/3x³y⁵
=(12÷3)×(x⁴÷x³)×(y²÷y⁵)
when you divide number with the same base, you subtract the numerators:
=4×(x⁴⁻³)×(y²⁻⁵)
simplifying this we get
=4xy⁻³
Answer: 4xy⁻³