## Elementary Algebra

$6\sqrt 2$
We break the square root into its factors, and then we simplify the factors that are perfect squares: $\sqrt 6\times\sqrt {12}$ =$\sqrt {6\times12}$ =$\sqrt {72}$ =$\sqrt {2\times36}$ =$\sqrt 2\times\sqrt {36}$ =$\sqrt 2\times6$ =$6\sqrt 2$