Answer
$\dfrac{4\sqrt{3y}}{y}$
Work Step by Step
RECALL:
For all non-negative real number $a$,
$\sqrt{a} \cdot \sqrt{a} = a$
Rationalize the denominator by multiplying $\sqrt3y$ to both the numerator and the denominator. Simplify using the rule above to obtain:
$\require{cancel}
=\dfrac{12 \cdot \sqrt{3y}}{\sqrt{3y} \cdot \sqrt{3y}}
\\=\dfrac{12\sqrt{3y}}{3y}
\\=\dfrac{\cancel{12}4\sqrt{3y}}{\cancel{3}y}
\\=\dfrac{4\sqrt{3y}}{y}
$
