Answer:
2
----------
5w^11
Explanation:
8/20 reduces to 2/5, and (w^(-2)) / w^9 becomes 1 / w^11.
Overall, #20 reduces to:
2
----------
5w^11
Recall the rule of exponents:
w^a
----------- = w^(a-b)
w^b
and note that
w^(-2)
------------ = w^(-2-9) = w^(-11) (same as above)
w^9