Answer:
-5/ (x^19 * y^12)
Explanation:
-15x^-10 * y ^ -3 * x^-9 * y^-9/3 (It's writing it like this.)
15 and 3 have a GCF of 3.
-5x^-10 * y^-3 * x^-9 * y^-9/1
Reduce similar occurrences. *twice in a row*
-5x^(-10 + (-9)) * y^(-3 + (-9))/1
Remove extra signs *twice in a row*
-5x^(-10 - 9) * y^(-3 - 9)/1
Remove extraneous 1.
-5x^(-10 - 9) * y^(-3 - 9)
Add integers.
-5x^-19 * y^-12
Negative powers change multiplication to division.
-5 / (x^19 * y^12) is the final answer.
Even with that, the simplified answer wouldn't have negative exponents because of the negative powers rule.