[tex]\displaystyle \frac{3- \sqrt{3} }{3 \sqrt{2} - \sqrt{6} } = \frac{(3- \sqrt{3} )(3 \sqrt{2} + \sqrt{6} )}{18-6} = \frac{9 \sqrt{2} +3 \sqrt{6} -3 \sqrt{6} - \sqrt{18} }{12} = \\ \\ = \frac{9 \sqrt{2} -3 \sqrt{2} }{12} = \frac{6 \sqrt{2} }{12} = \frac{ \sqrt{2} }{2} [/tex]
