Answer
$\frac{15-3\sqrt 2}{23}$
Work Step by Step
Multiply the top and bottom by the conjugate of the denominator to simplify.
$\frac{3}{5+\sqrt 2}$
$\frac{3}{5+\sqrt 2}\times\frac{5-\sqrt 2}{5-\sqrt 2}$
$\frac{15-3\sqrt 2}{25-2}$
$\frac{15-3\sqrt 2}{23}$