Answer
$a\cdot b^2$
Work Step by Step
For any variable with a negative exponent, you can flip the variable onto the other side of the fraction (numerator to denominator or denominator to numerator) and change the negative exponent to a positive exponent. For any variable with a positive exponent, if you flip the variable onto the other side of the fraction, you will change the positive exponent into a negative exponent.
$\frac{a}{b^{-2}} = \frac{a*b^2}{1} = a \cdot b^2$