[tex]\frac{1}{1-\sqrt{2}} -\frac{7}{3-\sqrt{2}} +\sqrt{8} \\
rationalizand cu conjugata obtinem \\
\frac{1+\sqrt{2}}{(1+\sqrt{2})(1-\sqrt{2)}} -\frac{7}{(3-\sqrt{2)(3+\sqrt{2)}}} +2\sqrt{2} \\
\frac{1+\sqrt{2}}{1^{2}-(\sqrt{2)^{2}}} -\frac{7(3+\sqrt{2)}}{3^{2}-(\sqrt{2)^{2})}} +2\sqrt{2} \\
\frac{1+\sqrt{2}}{1-2}}-\frac{7(3+\sqrt{2)}}{9-2}} +2\sqrt{2}\\
\frac{1+\sqrt{2}}{-1}}-\frac{7(3+\sqrt{2)}}{7}} +2\sqrt{2}\\
-1-\sqrt{2} -3-\sqrt{2}+2\sqrt{2}\\
-4[/tex]