Answer
$x=6(\sqrt 10-\sqrt 5)$
Work Step by Step
$\frac{x}{\sqrt 10}=\frac{3\sqrt 2}{\sqrt 2+1}$
$(\sqrt 2+1)x=6\sqrt 5$
$x=\frac{6\sqrt 5}{\sqrt 2+1}$
Multiply the right side with $\frac{\sqrt 2-1}{\sqrt 2-1}$
$x=\frac{6\sqrt 5(\sqrt 2-1)}{2-1}$
$x=6\sqrt 10-6\sqrt 5$
$x=6(\sqrt 10-\sqrt 5)$
