Answer:
2b^2
--------------
5a^4
Explanation:
2a^-4
-------------
5b^-2
Negative exponents go to the denominator when they are in the numerator
and to the numerator when they are in the denominator
a^-4 becomes 1/a^4
1/b^-2 becomes b^2
2/5 * 1/a^4 * b^2
2*b^2 * 1/5a^4
Rewriting
2b^2
--------------
5a^4