The rule is simple when dividing Polynomials. When It comes to exponential you just deduct/ subtract it. When it comes to numbers you divide it.
This is the illustration
-12x^8y^8
3x^4y^2 divide -12 by 3 and subtract their exponents, 8 - 4. So it will be
-4x^4
The same rule applies to the next which is y. Since it has no number attached to it. It is considered as 1. So you will only deduct their exponential form which is 8 - 2.
so the final answer would be -4x^4y^6