## Elementary Algebra

$\frac{-2\sqrt{ab}}{5}$
In order to solve this problem, we use the rules of exponents to get the square root of b in the numerator: $\frac{ -2\sqrt{ab^2}\sqrt{b^{-1}}}{5} \\ \frac{-2\sqrt{ab^{2-1}}}{5}$ $\frac{-2\sqrt{ab}}{5}$