Answer
$\frac{\sqrt a b}{b}$
Work Step by Step
$\frac{a \sqrt b}{b \sqrt a}$
We need to rationalize the denominator by multiply it by $\sqrt a$ because we cannot have a radical in the denominator
$\frac{a \sqrt b}{b \sqrt a} \times \frac{\sqrt a}{\sqrt a}$
We multiply the radicals and bring them under one radical
$\frac{a \sqrt a b}{ba}$
The a in the numerator cancels out the a in the denominator.
$\frac{\sqrt a b}{b}$
