Answer
$3\sqrt 3$
Work Step by Step
$\sqrt 3 + \sqrt 12$
Split $\sqrt 12$ into two factors such that one is a perfect square.
$= \sqrt 3 + \sqrt (4 \times 3)$
$= \sqrt 3 + \sqrt 4 \times \sqrt 3$
$= \sqrt 3 + 2\sqrt 3$
Apply Distributive property
$= (1 + 2) \sqrt 3$
$= 3\sqrt 3$